diff --git a/CHANGELOG.md b/CHANGELOG.md
index e89ac59d3..eb4cc43a3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 - Use Time instead of DateTime objects
 - Fix a bug: wrong times in admin/event monitoring
 - Fix a bug: daylight saving time is ignored and result in wrong dates and/or times when dealing around the DST day
+- Fix a bug: date shift in event creation/update
 - Fix a bug: unable to run `rails db:seed` when first setup Fab-manager
 
 ## v5.6.11 2023 February 07
diff --git a/app/services/availabilities/create_availabilities_service.rb b/app/services/availabilities/create_availabilities_service.rb
index ed2ee51fd..88d1a9258 100644
--- a/app/services/availabilities/create_availabilities_service.rb
+++ b/app/services/availabilities/create_availabilities_service.rb
@@ -5,7 +5,7 @@ class Availabilities::CreateAvailabilitiesService
   def create(availability, occurrences)
     occurrences = [] if occurrences.nil?
 
-    availability.update_attributes(occurrence_id: availability.id)
+    availability.update(occurrence_id: availability.id)
     create_slots(availability)
 
     occurrences.each do |o|
diff --git a/app/services/event_service.rb b/app/services/event_service.rb
index 7a6adcaf6..639353313 100644
--- a/app/services/event_service.rb
+++ b/app/services/event_service.rb
@@ -33,8 +33,8 @@ class EventService
     end
 
     def date_range(starting, ending, all_day)
-      start_date = Date.parse(starting[:date])
-      end_date = Date.parse(ending[:date])
+      start_date = Time.zone.parse(starting[:date])
+      end_date = Time.zone.parse(ending[:date])
       start_time = starting[:time] ? Time.zone.parse(starting[:time]) : nil
       end_time = ending[:time] ? Time.zone.parse(ending[:time]) : nil
       if all_day || start_time.nil? || end_time.nil?
diff --git a/test/integration/events/timezone_test.rb b/test/integration/events/timezone_test.rb
new file mode 100644
index 000000000..b7b5700ea
--- /dev/null
+++ b/test/integration/events/timezone_test.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+module Events; end
+
+class Events::TimezoneTest < ActionDispatch::IntegrationTest
+  setup do
+    admin = User.with_role(:admin).first
+    login_as(admin, scope: :user)
+  end
+
+  test 'create an event from a negative timezone' do
+    # Create a new event
+    post '/api/events',
+         params: {
+           event: {
+             title: 'Street child skateboard',
+             description: '<p>Build your own skateboard for children to ride in the street</p>',
+             category_id: 2,
+             start_date: '2023-06-14T20:00:00.000-04:00',
+             end_date: '2023-06-14T20:00:00.000-04:00',
+             start_time: '09:48',
+             end_time: '11:48',
+             recurrence: 'none',
+             recurrence_end_at: '',
+             nb_total_places: 'NaN',
+             amount: '35',
+             advanced_accounting_attributes: {
+               code: '',
+               analytical_section: ''
+             },
+             event_image_attributes: {
+               attachment: fixture_file_upload('/files/event/Skateboard.jpg')
+             }
+           }
+         }.to_json,
+         headers: default_headers
+
+    # Check response format & status
+    assert_equal 201, response.status, response.body
+    assert_equal Mime[:json], response.content_type
+
+    # Check the event was created correctly
+    event = json_response(response.body)
+    e = Event.find_by(id: event[:id])
+    assert_not_nil e, 'Event was not created in database'
+
+    assert_equal '2023-06-15', e.availability.start_at.to_date.iso8601
+    assert_equal '2023-06-15', e.availability.end_at.to_date.iso8601
+    assert_equal '09:48', e.availability.start_at.strftime('%R')
+    assert_equal '11:48', e.availability.end_at.strftime('%R')
+  end
+end