diff --git a/CHANGELOG.md b/CHANGELOG.md
index e18eba809..3c7d9d49c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 - OpenAPI users endpoint offer ability to filter by created_after
 - Fix a bug: providing an array of attributes to filter OpenApi data, results in error
 - Fix a bug: unable to manage stocks on new products
+- Fix a bug: unsupported param[] syntax in OpenAPI
 - Updated react-modal to 3.16.1
 - Updated tiptap editor and its dependencies to 2.0.0-beta.204
 - [TODO DEPLOY] `rails fablab:setup:build_accounting_lines`
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 954945ebf..f6302438b 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -85,6 +85,8 @@ module ApplicationHelper
 
   # Return the given parameter as it, or as an array if it can be parsed as an array
   def may_array(param)
+    return param if param.is_a?(Array)
+
     return param unless param&.chars&.first == '[' && param&.chars&.last == ']'
 
     param.gsub(/[\[\]]/i, '').split(',')
diff --git a/test/integration/open_api/users_test.rb b/test/integration/open_api/users_test.rb
index 494d1b63a..40eb80e7e 100644
--- a/test/integration/open_api/users_test.rb
+++ b/test/integration/open_api/users_test.rb
@@ -38,6 +38,16 @@ class OpenApi::UsersTest < ActionDispatch::IntegrationTest
     assert(users[:users].all? { |user| [3, 4, 5].include?(user[:id]) })
   end
 
+  test 'list all users filtering by IDs other syntax' do
+    get '/open_api/v1/users?user_id[]=3&user_id[]=4&user_id[]=5', headers: open_api_headers(@token)
+    assert_response :success
+    assert_equal Mime[:json], response.content_type
+
+    users = json_response(response.body)
+    assert users[:users].count.positive?
+    assert(users[:users].all? { |user| [3, 4, 5].include?(user[:id]) })
+  end
+
   test 'list a user filtering by ID' do
     get '/open_api/v1/users?user_id=2', headers: open_api_headers(@token)
     assert_response :success