diff --git a/DbFirst.API/Controllers/CatalogsController.cs b/DbFirst.API/Controllers/CatalogsController.cs
index 254b39d..92518b8 100644
--- a/DbFirst.API/Controllers/CatalogsController.cs
+++ b/DbFirst.API/Controllers/CatalogsController.cs
@@ -50,17 +50,6 @@ public class CatalogsController : ControllerBase
     [HttpPut("{id:int}")]
     public async Task<ActionResult<CatalogReadDto>> Update(int id, CatalogWriteDto dto, CancellationToken cancellationToken)
     {
-        var current = await _mediator.Send(new GetCatalogByIdQuery(id), cancellationToken);
-        if (current == null)
-        {
-            return NotFound();
-        }
-        if (dto.UpdateProcedure == CatalogUpdateProcedure.Update &&
-            !string.Equals(current.CatTitle, dto.CatTitle, StringComparison.OrdinalIgnoreCase))
-        {
-            return BadRequest("Titel kann nicht geändert werden.");
-        }
-
         var updated = await _mediator.Send(new UpdateCatalogCommand(id, dto), cancellationToken);
         if (updated == null)
         {
diff --git a/DbFirst.Application/Catalogs/Commands/UpdateCatalogHandler.cs b/DbFirst.Application/Catalogs/Commands/UpdateCatalogHandler.cs
index 9e25ef5..193cd1a 100644
--- a/DbFirst.Application/Catalogs/Commands/UpdateCatalogHandler.cs
+++ b/DbFirst.Application/Catalogs/Commands/UpdateCatalogHandler.cs
@@ -25,18 +25,20 @@ public class UpdateCatalogHandler : IRequestHandler<UpdateCatalogCommand, Catalo
             return null;
         }
 
+        if (request.Dto.UpdateProcedure == CatalogUpdateProcedure.Update &&
+            !string.Equals(existing.CatTitle, request.Dto.CatTitle, StringComparison.OrdinalIgnoreCase))
+        {
+            throw new InvalidOperationException("Titel kann nicht geändert werden.");
+        }
+
         var entity = _mapper.Map<VwmyCatalog>(request.Dto);
         entity.Guid = request.Id;
-        entity.CatTitle = request.Dto.UpdateProcedure == CatalogUpdateProcedure.Update
-            ? existing.CatTitle
-            : request.Dto.CatTitle;
         entity.AddedWho = existing.AddedWho;
         entity.AddedWhen = existing.AddedWhen;
         entity.ChangedWho = "system";
         entity.ChangedWhen = DateTime.UtcNow;
 
-        var procedure = request.Dto.UpdateProcedure;
-        var updated = await _repository.UpdateAsync(request.Id, entity, procedure, cancellationToken);
+        var updated = await _repository.UpdateAsync(request.Id, entity, request.Dto.UpdateProcedure, cancellationToken);
         return updated == null ? null : _mapper.Map<CatalogReadDto>(updated);
     }
 }