diff --git a/src/FilterService/FilterType/ElasticSearch/SelectCategory.php b/src/FilterService/FilterType/ElasticSearch/SelectCategory.php
index 54d53ca14..87ad87330 100644
--- a/src/FilterService/FilterType/ElasticSearch/SelectCategory.php
+++ b/src/FilterService/FilterType/ElasticSearch/SelectCategory.php
@@ -77,7 +77,7 @@ public function addCondition(AbstractFilterDefinitionType $filterDefinition, Pro
         $currentFilter[$filterDefinition->getField()] = $value;
 
         if (!empty($value)) {
-            $value = trim($value);
+            $value = trim((string)$value);
             $productList->addCondition($value, $filterDefinition->getField());
         }