diff --git a/backend/tests/Squidex.Web.Tests/UrlDecodeRouteParamsAttributeTests.cs b/backend/tests/Squidex.Web.Tests/UrlDecodeRouteParamsAttributeTests.cs
new file mode 100644
index 000000000..a0c17e3ee
--- /dev/null
+++ b/backend/tests/Squidex.Web.Tests/UrlDecodeRouteParamsAttributeTests.cs
@@ -0,0 +1,40 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using System.Collections.Generic;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Abstractions;
+using Microsoft.AspNetCore.Mvc.Filters;
+using Microsoft.AspNetCore.Routing;
+using Xunit;
+
+namespace Squidex.Web
+{
+    public class UrlDecodeRouteParamsAttributeTests
+    {
+        [Fact]
+        public void Should_url_decode_params()
+        {
+            var sut = new UrlDecodeRouteParamsAttribute();
+
+            var actionContext = new ActionContext(new DefaultHttpContext(), new RouteData(), new ActionDescriptor
+            {
+                FilterDescriptors = new List<FilterDescriptor>()
+            });
+
+            var actionExecutingContext = new ActionExecutingContext(actionContext, new List<IFilterMetadata>(), new Dictionary<string, object>
+            {
+                ["key"] = "path%2Fto%2Fsomething"
+            }, null!);
+
+            sut.OnActionExecuting(actionExecutingContext);
+
+            Assert.Equal("path/to/something", actionExecutingContext.ActionArguments["key"]);
+        }
+    }
+}