Macina searchbox TS-config. Put this TS in your Pageroot Template.
Important: Make sure that you have been installed the extension (EXTKEY: indexed_search).

Change Stylesheet: typo3/sysext/indexed_search/ext_typoscript_setup.txt
Translate: Indexed search in german -> Insatall german language in Typo3 and set this line into page setup: config.language=de