Subject: Czechia or the Czech Republic or what ?
Hi Baerbel, you can use Czechia (similar to Tschechien) or Czech Republic. Czech Republic is used for official documents, but Czechia is the recommended name by the Ministry of Foreign Affairs of the Czech Republic. In Spanish is Chequia, and believe me, I found easier the german form. Check the following URL :

http://www.czechia.org/

Regards from Covadonga in Bilbao (Spain)