diff --git a/changelog/62_UNRELEASED_xxxx-xx-xx.md b/changelog/62_UNRELEASED_xxxx-xx-xx.md
index 362cf26a..5185c185 100644
--- a/changelog/62_UNRELEASED_xxxx-xx-xx.md
+++ b/changelog/62_UNRELEASED_xxxx-xx-xx.md
@@ -88,3 +88,4 @@
 - Fixed that due soon products with `due_type` = "Expiration date" were missing in `due_products` of the `/stock/volatile` endpoint
 - Fixed that `PUT/DELETE /objects/{entity}/{objectId}` produced an internal server error when the given object id was invalid (now returns `400 Bad Request`)
 - Fixed that hyphens in filter values did not work
+- Fixed that cyrillic letters were not allowed in filter values
diff --git a/controllers/BaseApiController.php b/controllers/BaseApiController.php
index 5eb34bd9..96a2d343 100644
--- a/controllers/BaseApiController.php
+++ b/controllers/BaseApiController.php
@@ -12,7 +12,7 @@ class BaseApiController extends BaseController
 
 	const PATTERN_OPERATOR = '!?(=|~|<|>|(>=)|(<=)|(§))';
 
-	const PATTERN_VALUE = '[A-Za-z_0-9.$#^|-]+';
+	const PATTERN_VALUE = '[A-Za-z\x{0400}-\x{04FF}_0-9.$#^|-]+';
 
 	public function __construct(\DI\Container $container)
 	{
@@ -90,7 +90,7 @@ class BaseApiController extends BaseController
 			preg_match(
 				'/(?P<field>' . self::PATTERN_FIELD . ')'
 				. '(?P<op>' . self::PATTERN_OPERATOR . ')'
-				. '(?P<value>' . self::PATTERN_VALUE . ')/',
+				. '(?P<value>' . self::PATTERN_VALUE . ')/u',
 				$q,
 				$matches
 			);