diff --git a/app/frontend/src/javascript/controllers/events.js.erb b/app/frontend/src/javascript/controllers/events.js.erb
index c08a98530..eceaacc9f 100644
--- a/app/frontend/src/javascript/controllers/events.js.erb
+++ b/app/frontend/src/javascript/controllers/events.js.erb
@@ -644,7 +644,7 @@ Application.Controllers.controller('ShowEventController', ['$scope', '$state', '
             if (!user.booked) {
               return false;
             }
-            if ($scope.enableChildValidationRequired && user.booked.type === 'Child' && !user.booked.is_valid) {
+            if ($scope.enableChildValidationRequired && user.booked.type === 'Child' && !user.booked.validated_at) {
               return false;
             }
           }
@@ -675,9 +675,10 @@ Application.Controllers.controller('ShowEventController', ['$scope', '$state', '
 
       // get the current user's reservations into $scope.reservations
       if ($scope.currentUser) {
-        getReservations($scope.event.id, 'Event', $scope.currentUser.id);
-        getChildren($scope.currentUser.id).then(function (children) {
-          updateNbReservePlaces();
+        getReservations($scope.event.id, 'Event', $scope.currentUser.id).then(function (reservations) {
+          getChildren($scope.currentUser.id).then(function (children) {
+            updateNbReservePlaces();
+          });
         });
       }
 
@@ -696,7 +697,7 @@ Application.Controllers.controller('ShowEventController', ['$scope', '$state', '
      * @param user_id {number} the user's id (current or managed)
      */
     const getReservations = function (reservable_id, reservable_type, user_id) {
-      Reservation.query({
+      return Reservation.query({
         reservable_id,
         reservable_type,
         user_id
@@ -727,6 +728,14 @@ Application.Controllers.controller('ShowEventController', ['$scope', '$state', '
           }
         }
       }
+      for (const r of $scope.reservations) {
+        for (const user of r.booking_users_attributes) {
+          const key = user.booked_type === 'User' ? `user_${user.booked_id}` : `child_${user.booked_id}`;
+          if (key === userKey) {
+            return true;
+          }
+        }
+      }
       return false;
     };
 
@@ -748,7 +757,7 @@ Application.Controllers.controller('ShowEventController', ['$scope', '$state', '
             name: child.first_name + ' ' + child.last_name,
             id: child.id,
             type: 'Child',
-            is_valid: child.is_valid,
+            validated_at: child.validated_at,
             birthday: child.birthday
           });
         }
@@ -761,7 +770,10 @@ Application.Controllers.controller('ShowEventController', ['$scope', '$state', '
      */
     const updateNbReservePlaces = function () {
       if ($scope.event.event_type === 'family') {
-        const maxPlaces = $scope.children.length + 1;
+        const reservedPlaces = $scope.reservations.reduce((sum, reservation) => {
+          return sum + reservation.booking_users_attributes.length;
+        }, 0);
+        const maxPlaces = $scope.children.length + 1 - reservedPlaces;
         if ($scope.event.nb_free_places > maxPlaces) {
           $scope.reserve.nbPlaces.normal = __range__(0, maxPlaces, true);
           for (let evt_px_cat of Array.from($scope.event.event_price_categories_attributes)) {
@@ -976,11 +988,11 @@ Application.Controllers.controller('ShowEventController', ['$scope', '$state', '
       Reservation.get({ id: invoice.main_object.id }, function (reservation) {
         $scope.event.nb_free_places = $scope.event.nb_free_places - reservation.total_booked_seats;
         $scope.reservations.push(reservation);
+        resetEventReserve();
+        updateNbReservePlaces();
+        $scope.reserveSuccess = true;
+        $scope.coupon.applied = null;
       });
-      resetEventReserve();
-      updateNbReservePlaces();
-      $scope.reserveSuccess = true;
-      $scope.coupon.applied = null;
       if ($scope.currentUser.role === 'admin') {
         return $scope.ctrl.member = null;
       }
diff --git a/app/frontend/templates/events/show.html b/app/frontend/templates/events/show.html
index 045e35deb..0f0183e5b 100644
--- a/app/frontend/templates/events/show.html
+++ b/app/frontend/templates/events/show.html
@@ -142,7 +142,7 @@
                               class="form-control">
                         <option value=""></option>
                       </select>
-                      <uib-alert type="danger" ng-if="enableChildValidationRequired && user.booked && user.booked.type === 'Child' && !user.booked.is_valid" style="margin-bottom: 0.8rem;">
+                      <uib-alert type="danger" ng-if="enableChildValidationRequired && user.booked && user.booked.type === 'Child' && !user.booked.validated_at" style="margin-bottom: 0.8rem;">
                         <span class="text-sm">
                           <i class="fa fa-warning"></i>
                           <span translate>{{ 'app.shared.cart.child_validation_required_alert' }}</span>
diff --git a/app/models/child.rb b/app/models/child.rb
index 3d752ac54..e91ff6b83 100644
--- a/app/models/child.rb
+++ b/app/models/child.rb
@@ -11,7 +11,7 @@ class Child < ApplicationRecord
   validates :first_name, presence: true
   validates :last_name, presence: true
   # validates :email, presence: true, format: { with: Devise.email_regexp }
-  validate :validate_age
+  # validate :validate_age
 
   # birthday should less than 18 years ago
   def validate_age