diff --git a/Classes/Controller/ListViewController.php b/Classes/Controller/ListViewController.php
index 93cbbae23..66bb47835 100644
--- a/Classes/Controller/ListViewController.php
+++ b/Classes/Controller/ListViewController.php
@@ -81,7 +81,7 @@ public function mainAction(): void
 
         // extract collection(s) from collection parameter
         $collections = [];
-        if ($this->searchParams['collection']) {
+        if (array_key_exists('collection', $this->searchParams)) {
             foreach(explode(',', $this->searchParams['collection']) as $collectionEntry) {
                 $collections[] = $this->collectionRepository->findByUid((int) $collectionEntry);
             }
diff --git a/Classes/Controller/SearchController.php b/Classes/Controller/SearchController.php
index 8923e7436..ae69761d1 100644
--- a/Classes/Controller/SearchController.php
+++ b/Classes/Controller/SearchController.php
@@ -390,7 +390,7 @@ private function addCollectionsQuery(string $query): string
         // if collections are given, we prepare the collections query string
         // extract collections from collection parameter
         $collections = null;
-        if ($this->searchParams['collection']) {
+        if (array_key_exists('collection', $this->searchParams)) {
             foreach (explode(',', $this->searchParams['collection']) as $collectionEntry) {
                 $collections[] = $this->collectionRepository->findByUid((int) $collectionEntry);
             }