diff --git a/lib/private/Files/ObjectStore/S3ObjectTrait.php b/lib/private/Files/ObjectStore/S3ObjectTrait.php
index 8b8cc444ad99e..a81e215db6d88 100644
--- a/lib/private/Files/ObjectStore/S3ObjectTrait.php
+++ b/lib/private/Files/ObjectStore/S3ObjectTrait.php
@@ -85,14 +85,13 @@ public function readObject($urn) {
 	}
 
 	/**
-	 * @param string   $urn    the unified resource name used to identify the object
+	 * @param string $urn the unified resource name used to identify the object
 	 * @param resource $stream stream with the data to write
-	 *
+	 * @param string|null $mimetype the mimetype to set for the remove object @since 22.0.0
 	 * @throws \Exception when something goes wrong, message will be logged
-	 *
 	 * @since 7.0.0
 	 */
-	public function writeObject($urn, $stream) {
+	public function writeObject($urn, $stream, string $mimetype = null)
 		$count = 0;
 		$countStream = CallbackWrapper::wrap($stream, function ($read) use (&$count) {
 			$count += $read;
@@ -102,7 +101,9 @@ public function writeObject($urn, $stream) {
 			'bucket' => $this->bucket,
 			'key' => $urn,
 			'part_size' => $this->uploadPartSize,
-			'params' => $this->getSseKmsPutParameters(),
+			'params' => [
+				'ContentType' => $mimetype
+			] + $this->getSseKmsPutParameters(),
 		];
 		$uploader = new MultipartUploader($this->getConnection(), $countStream, $s3params);
 
@@ -148,7 +149,7 @@ public function deleteObject($urn) {
 	public function objectExists($urn) {
 		return $this->getConnection()->doesObjectExist($this->bucket, $urn);
 	}
-
+	
 	/**
 	 * S3 copy command with SSE KMS key handling.
 	 */