diff --git a/src/Filter/In.php b/src/Filter/In.php
index ab23187bb6f3461371695fbaa436aab6ced662a4..a8c63f79fa1ce4594d02c6f30a31751d0c6211e6 100644
--- a/src/Filter/In.php
+++ b/src/Filter/In.php
@@ -13,7 +13,7 @@ final class In extends HttpFilter
     /** @throws FilterParameterValueIsNullException */
     public function addToQuery(QueryBuilder $queryBuilder): QueryBuilder
     {
-        if ($this->getHttpValue() === null) {
+        if ($this->getHttpValue() === null || ! is_array($this->getHttpValue())) {
             throw new FilterParameterValueIsNullException($this->field);
         }