diff --git a/app/assets/javascripts/controllers/admin/members.coffee.erb b/app/assets/javascripts/controllers/admin/members.coffee.erb
index 55d79c0ec..14b2c42a9 100644
--- a/app/assets/javascripts/controllers/admin/members.coffee.erb
+++ b/app/assets/javascripts/controllers/admin/members.coffee.erb
@@ -423,11 +423,40 @@ Application.Controllers.controller "EditMemberController", ["$scope", "$state",
       templateUrl: '<%= asset_path "wallet/credit_modal.html" %>'
       controller: ['$scope', '$uibModalInstance', 'Wallet', ($scope, $uibModalInstance, Wallet) ->
 
+        # default: do not generate a refund invoice
+        $scope.generate_avoir = false
+
+        # date of the generated refund invoice
+        $scope.avoir_date = null
+
+        # optional description shown on the refund invoice
+        $scope.description = ''
+
+        # default configuration for the avoir date selector widget
+        $scope.datePicker =
+          format: Fablab.uibDateFormat
+          opened: false
+          options:
+            startingDay: Fablab.weekStartingDay
+
+        ##
+        # Callback to open/close the date picker
+        ##
+        $scope.toggleDatePicker = ($event) ->
+          $event.preventDefault()
+          $event.stopPropagation()
+          $scope.datePicker.opened = !$scope.datePicker.opened
+
         ##
         # Modal dialog validation callback
         ##
         $scope.ok = ->
-          Wallet.credit { id: wallet.id }, { amount: $scope.amount }, (_wallet)->
+          Wallet.credit { id: wallet.id },
+            amount: $scope.amount
+            avoir: $scope.generate_avoir
+            avoir_date: $scope.avoir_date
+            avoir_description: $scope.description
+          , (_wallet)->
 
             growl.success(_t('wallet_credit_successfully'))
             $uibModalInstance.close(_wallet)
diff --git a/app/assets/templates/wallet/credit_modal.html.erb b/app/assets/templates/wallet/credit_modal.html.erb
index 7624e12a9..80e0baf54 100644
--- a/app/assets/templates/wallet/credit_modal.html.erb
+++ b/app/assets/templates/wallet/credit_modal.html.erb
@@ -3,11 +3,18 @@
   <h1 translate>{{ 'credit_title' }}</h1>
 </div>
 <div class="modal-body">
+
+  <div class="alert alert-warning m-b-md m-b-sm">
+    <i class="fa fa-warning m-sm inline" aria-hidden="true"></i>
+    <div class="inline pull-right width-90 m-t-n-xs" translate>{{ 'warning_uneditable_credit' }}</div>
+  </div>
+
   <form name="walletForm" ng-class="{'has-error': walletForm.amount.$dirty && walletForm.amount.$invalid}">
     <div class="text-right amountGroup m-r-md">
-      <span class="beforeAmount" translate>{{ 'credit_label' }}</span>
+      <label for="amount" class="beforeAmount" translate>{{ 'credit_label' }}</label>
       <input class="form-control m-l"
              type="number"
+             id="amount"
              name="amount"
              ng-model="amount"
              required min="1"
@@ -16,10 +23,11 @@
       <span class="help-block" ng-show="walletForm.amount.$dirty && walletForm.amount.$error.required" translate>{{'amount_is_required'}}</span>
       <span class="help-block" ng-show="walletForm.amount.$dirty && walletForm.amount.$error.min">{{ 'amount_minimum_1' | translate }} {{currencySymbol}}.</span>
     </div>
-    <div class="text-right amountGroup m-t m-r-md">
-      <span class="beforeAmount" translate>{{ 'confirm_credit_label' }}</span>
+    <div class="text-right amountGroup m-t m-r-md" ng-class="{'has-error': walletForm.amount_confirm.$dirty && walletForm.amount_confirm.$invalid }">
+      <label for="amount_confirm" class="beforeAmount" translate>{{ 'confirm_credit_label' }}</label>
       <input class="form-control m-l"
              type="number"
+             id="amount_confirm"
              name="amount_confirm"
              ng-model="amount_confirm"
              required
@@ -30,12 +38,53 @@
       <span class="help-block" ng-show="walletForm.amount_confirm.$dirty && walletForm.amount_confirm.$error.required" translate>{{'amount_confirm_is_required'}}</span>
       <span class="help-block" ng-show="walletForm.amount_confirm.$dirty && walletForm.amount_confirm.$error.pattern">{{ 'amount_confirm_does_not_match' | translate }}</span>
     </div>
-  </form>
 
-  <div class="alert alert-warning m-t-md m-b-sm">
-    <i class="fa fa-warning m-sm inline" aria-hidden="true"></i>
-    <div class="inline pull-right width-90 m-t-n-xs" translate>{{ 'warning_uneditable_credit' }}</div>
-  </div>
+    <hr/>
+    <div class="text-right m-t">
+      <label for="generate_avoir" translate>{{ 'generate_a_refund_invoice' }}</label>
+      <div class="inline m-l">
+        <input bs-switch
+               ng-model="generate_avoir"
+               id="generate_avoir"
+               name="generate_avoir"
+               type="checkbox"
+               switch-on-text="{{ 'yes' | translate }}"
+               switch-off-text="{{ 'no' | translate }}"
+               switch-animate="true"/>
+      </div>
+    </div>
+
+    <div ng-show="generate_avoir">
+      <div class="m-t" ng-class="{'has-error': walletForm.avoir_date.$dirty && walletForm.avoir_date.$invalid }">
+        <label  for="avoir_date" translate>{{ 'creation_date_for_the_refund' }}</label>
+          <div class="input-group">
+            <span class="input-group-addon"><i class="fa fa-calendar"></i></span>
+            <input type="text"
+                   class="form-control"
+                   id="avoir_date"
+                   name="avoir_date"
+                   ng-model="avoir_date"
+                   uib-datepicker-popup="{{datePicker.format}}"
+                   datepicker-options="datePicker.options"
+                   is-open="datePicker.opened"
+                   placeholder="{{datePicker.format}}"
+                   ng-click="toggleDatePicker($event)"
+                   ng-required="generate_avoir"/>
+          </div>
+        <span class="help-block" ng-show="walletForm.avoir_date.$dirty && walletForm.avoir_date.$error.required" translate>{{ 'creation_date_is_required' }}</span>
+      </div>
+
+      <div class="m-t">
+        <label for="description" translate>{{ 'description_(optional)' }}</label>
+        <p translate>{{ 'will_appear_on_the_refund_invoice' }}</p>
+        <textarea class="form-control m-t-sm"
+                  id="description"
+                  name="description"
+                  ng-model="description">
+        </textarea>
+      </div>
+    </div>
+  </form>
 
 </div>
 <div class="modal-footer">
diff --git a/app/controllers/api/invoices_controller.rb b/app/controllers/api/invoices_controller.rb
index 22f210a68..2a0712d2e 100644
--- a/app/controllers/api/invoices_controller.rb
+++ b/app/controllers/api/invoices_controller.rb
@@ -57,7 +57,7 @@ class API::InvoicesController < API::ApiController
 
   end
 
-  # only for create avoir
+  # only for create refund invoices (avoir)
   def create
     authorize Invoice
     invoice = Invoice.only_invoice.find(avoir_params[:invoice_id])
diff --git a/app/controllers/api/wallet_controller.rb b/app/controllers/api/wallet_controller.rb
index 5ff142155..58f301c1f 100644
--- a/app/controllers/api/wallet_controller.rb
+++ b/app/controllers/api/wallet_controller.rb
@@ -14,13 +14,22 @@ class API::WalletController < API::ApiController
   end
 
   def credit
-    @wallet = Wallet.find(params[:id])
+    @wallet = Wallet.find(credit_params[:id])
     authorize @wallet
     service = WalletService.new(user: current_user, wallet: @wallet)
-    if service.credit(params[:amount].to_f)
+    transaction = service.credit(credit_params[:amount].to_f)
+    if transaction
+      if credit_params[:avoir]
+        service.create_avoir(transaction, credit_params[:avoir_date], credit_params[:avoir_description])
+      end
       render :show
     else
       head 422
     end
   end
+
+  private
+  def credit_params
+    params.permit(:id, :amount, :avoir, :avoir_date, :avoir_description)
+  end
 end
diff --git a/app/pdfs/pdf/invoice.rb b/app/pdfs/pdf/invoice.rb
index ab9b8b20e..faf79f42d 100644
--- a/app/pdfs/pdf/invoice.rb
+++ b/app/pdfs/pdf/invoice.rb
@@ -37,10 +37,12 @@ module PDF
         if Setting.find_by({name: 'invoice_code-active'}).value == 'true'
           text I18n.t('invoices.code', CODE:Setting.find_by({name: 'invoice_code-value'}).value), :leading => 3
         end
-        if invoice.is_a?(Avoir)
-          text I18n.t('invoices.order_number', NUMBER:invoice.invoice.order_number), :leading => 3
-        else
-          text I18n.t('invoices.order_number', NUMBER:invoice.order_number), :leading => 3
+        if invoice.invoiced_type != WalletTransaction.name
+          if invoice.is_a?(Avoir)
+            text I18n.t('invoices.order_number', NUMBER:invoice.invoice.order_number), :leading => 3
+          else
+            text I18n.t('invoices.order_number', NUMBER:invoice.order_number), :leading => 3
+          end
         end
         if invoice.is_a?(Avoir)
           text I18n.t('invoices.refund_invoice_issued_on_DATE', DATE:I18n.l(invoice.avoir_date.to_date))
@@ -68,7 +70,11 @@ module PDF
         # object
         move_down 25
         if invoice.is_a?(Avoir)
-          object = I18n.t('invoices.cancellation_of_invoice_REF', REF: invoice.invoice.reference)
+          if invoice.invoiced_type == WalletTransaction.name
+            object = I18n.t('invoices.wallet_credit')
+          else
+            object = I18n.t('invoices.cancellation_of_invoice_REF', REF: invoice.invoice.reference)
+          end
         else
           case invoice.invoiced_type
             when 'Reservation'
@@ -115,7 +121,7 @@ module PDF
 
 
           else ### Reservation
-            case invoice.invoiced.reservable_type
+            case invoice.invoiced.try(:reservable_type)
               ### Machine reservation
               when 'Machine'
                 details += I18n.t('invoices.machine_reservation_DESCRIPTION', DESCRIPTION: item.description)
@@ -130,6 +136,9 @@ module PDF
                 invoice.invoiced.tickets.each do |t|
                   details += "\n  "+I18n.t('invoices.other_rate_ticket', count: t.booked, NAME: t.event_price_category.price_category.name)
                 end
+              ### wallet credit
+              when nil
+                details = item.description
 
               ### Other cases (not expected)
               else
diff --git a/app/services/wallet_service.rb b/app/services/wallet_service.rb
index 23a824529..c8ebea8be 100644
--- a/app/services/wallet_service.rb
+++ b/app/services/wallet_service.rb
@@ -21,7 +21,7 @@ class WalletService
       end
       raise ActiveRecord::Rollback
     end
-    return false
+    false
   end
 
   ## debit an amount to wallet, if debit success then return a wallet transaction
@@ -35,6 +35,27 @@ class WalletService
       end
       raise ActiveRecord::Rollback
     end
-    return false
+    false
+  end
+
+  ## create a refund invoice associated with the given wallet transaction
+  def create_avoir(wallet_transaction, avoir_date, description)
+    avoir = Avoir.new
+    avoir.type = 'Avoir'
+    avoir.invoiced = wallet_transaction
+    avoir.avoir_date = avoir_date
+    avoir.created_at = avoir_date
+    avoir.description = description
+    avoir.avoir_mode = 'wallet'
+    avoir.subscription_to_expire = false
+    avoir.user_id = wallet_transaction.wallet.user_id
+    avoir.total = wallet_transaction.amount * 100.0
+    avoir.save!
+
+    ii = InvoiceItem.new
+    ii.amount = wallet_transaction.amount * 100.0
+    ii.description = I18n.t('invoices.wallet_credit')
+    ii.invoice = avoir
+    ii.save!
   end
 end
diff --git a/config/locales/app.shared.en.yml b/config/locales/app.shared.en.yml
index 8913ea48e..ffa74c5b3 100644
--- a/config/locales/app.shared.en.yml
+++ b/config/locales/app.shared.en.yml
@@ -324,6 +324,11 @@ en:
         credit_title: 'Credit wallet'
         credit_label: 'Set the amount to be credited'
         confirm_credit_label: 'Confirm the amount to be credited'
+        generate_a_refund_invoice: "Generate a refund invoice"
+        creation_date_for_the_refund: "Creation date for the refund"
+        creation_date_is_required: "Creation date is required."
+        description_(optional): "Description (optional):"
+        will_appear_on_the_refund_invoice: "Will appear on the refund invoice."
         to_credit: 'Credit'
         wallet_credit_successfully: "Wallet of user is credited successfully."
         a_problem_occurred_for_wallet_credit: "A problem is occurred while taking the credit of wallet"
diff --git a/config/locales/app.shared.fr.yml b/config/locales/app.shared.fr.yml
index fa1cdb010..3f83f502f 100644
--- a/config/locales/app.shared.fr.yml
+++ b/config/locales/app.shared.fr.yml
@@ -324,6 +324,11 @@ fr:
         credit_title: 'Créditer le porte-monnaie'
         credit_label: 'Indiquez le montant à créditer'
         confirm_credit_label: 'Confirmez le montant à créditer'
+        generate_a_refund_invoice: "Générer une facture d'avoir"
+        creation_date_for_the_refund: "Date d'émission de l'avoir"
+        creation_date_is_required: "La date d'émission est requise."
+        description_(optional): "Description (optionnelle) :"
+        will_appear_on_the_refund_invoice: "Apparaîtra sur la facture de remboursement."
         to_credit: 'Créditer'
         wallet_credit_successfully: "Le porte-monnaie de l'utilisateur a été chargé avec succès."
         a_problem_occurred_for_wallet_credit: "Un problème est survenu lors du chargement du porte-monnaie."
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 11dbd5fd8..56ff141a4 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -72,6 +72,7 @@ en:
     order_number: "Order #: %{NUMBER}"
     invoice_issued_on_DATE: "Invoice issued on %{DATE}"
     refund_invoice_issued_on_DATE: "Refund invoice issued on %{DATE}"
+    wallet_credit: "Wallet credit"
     cancellation_of_invoice_REF: "Cancellation of invoice %{REF}"
     reservation_of_USER_on_DATE_at_TIME: "Reservation of %{USER} on %{DATE} at %{TIME}"
     cancellation: "Cancellation"
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index 1cebdb59d..5a17e3fa4 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -72,6 +72,7 @@ fr:
     order_number: "N° Commande : %{NUMBER}"
     invoice_issued_on_DATE: "Facture éditée le %{DATE}"
     refund_invoice_issued_on_DATE: "Avoir édité le %{DATE}"
+    wallet_credit: "Crédit du porte-monnaie"
     cancellation_of_invoice_REF: "Annulation de la facture %{REF}"
     reservation_of_USER_on_DATE_at_TIME: "Réservation de %{USER} le %{DATE} à %{TIME}"
     cancellation: "Annulation"
diff --git a/test/integration/prices/compute_test.rb b/test/integration/prices/compute_test.rb
new file mode 100644
index 000000000..3a0231964
--- /dev/null
+++ b/test/integration/prices/compute_test.rb
@@ -0,0 +1,82 @@
+module Events
+  class AsAdminTest < ActionDispatch::IntegrationTest
+
+    setup do
+      admin = User.with_role(:admin).first
+      login_as(admin, scope: :user)
+    end
+
+    test 'compute price for a simple training' do
+      user = User.find_by(username: 'jdupond')
+      availability = Availability.find(2)
+      printer_training = availability.trainings.first
+
+      post '/api/prices/compute',
+           {
+               reservation: {
+                   user_id: user.id,
+                   reservable_id: printer_training.id,
+                   reservable_type: printer_training.class.name,
+                   slots_attributes: [
+                       {
+                           availability_id: availability.id,
+                           end_at: availability.end_at,
+                           offered: false,
+                           start_at: availability.start_at
+                       }
+                   ]
+               }
+           }.to_json,
+           default_headers
+
+      # Check response format & status
+      assert_equal 200, response.status, response.body
+      assert_equal Mime::JSON, response.content_type
+
+      # Check the price was computed correctly
+      price = json_response(response.body)
+      assert_equal (printer_training.trainings_pricings.where(group_id: user.group_id).first.amount / 100.0), price[:price], 'Computed price did not match training price'
+    end
+
+
+    test 'compute price for a machine reservation with an offered slot and a subscription' do
+      user = User.find_by(username: 'jdupond')
+      availability = Availability.find(3)
+      laser = availability.machines.where(id: 1).first
+      plan = Plan.where(group_id: user.group_id, interval: 'month').first
+
+      post '/api/prices/compute',
+           {
+               reservation: {
+                   user_id: user.id,
+                   reservable_id: laser.id,
+                   reservable_type: laser.class.name,
+                   plan_id: plan.id,
+                   slots_attributes: [
+                       {
+                           availability_id: availability.id,
+                           end_at: (availability.start_at + 1.hour).strftime('%Y-%m-%d %H:%M:%S.%9N Z'),
+                           offered: true,
+                           start_at: availability.start_at.strftime('%Y-%m-%d %H:%M:%S.%9N Z')
+                       },
+                       {
+                           availability_id: availability.id,
+                           end_at: (availability.start_at + 2.hour).strftime('%Y-%m-%d %H:%M:%S.%9N Z'),
+                           offered: false,
+                           start_at: (availability.start_at + 1.hour).strftime('%Y-%m-%d %H:%M:%S.%9N Z')
+                       }
+                   ]
+               }
+           }.to_json,
+           default_headers
+
+      # Check response format & status
+      assert_equal 200, response.status, response.body
+      assert_equal Mime::JSON, response.content_type
+
+      # Check the event was created correctly
+      price = json_response(response.body)
+      assert_equal ((laser.prices.where(group_id: user.group_id, plan_id: plan.id).first.amount + plan.amount) / 100.0), price[:price], 'Computed price did not match machine + subscription price'
+    end
+  end
+end
diff --git a/test/models/coupon_test.rb b/test/models/coupon_test.rb
index f1cef7ee7..d7358357a 100644
--- a/test/models/coupon_test.rb
+++ b/test/models/coupon_test.rb
@@ -1,6 +1,14 @@
 require 'test_helper'
 
 class CouponTest < ActiveSupport::TestCase
+
+  test 'valid coupon with percentage' do
+    c = Coupon.new({name: 'Hot deals', code: 'HOT15', percent_off: 15, validity_per_user: 'once', valid_until: (Time.now + 2.weeks), max_usages: 100, active: true})
+    assert c.valid?
+    assert_equal 'active', c.status, 'Invalid coupon status'
+    assert_equal 'percent_off', c.type, 'Invalid coupon type'
+  end
+
   test 'coupon must have a valid percentage' do
     c = Coupon.new({name: 'Amazing deal', code: 'DISCOUNT', percent_off: 200, validity_per_user: 'once'})
     assert c.invalid?