The postcard shows Ouarzazate in Morocco. Thank you Radim!
Radim's blog www.coverspostcardsworldwide.wordpress.com
Western Sahara is a disputed territory in the Maghreb region of North Africa. It's bordered by Morocco, Algeria, Mauritania and the Atlantic Ocean. Its territory is mainly consisting desert flatlands. The biggest city of Western Sahara is El Aaiún, which is home to nearly 40% of the population.
Radim bought postcards at the airport in Laâyoune, all showing Morocco. He sent my postcard from El Aaiún (Laâyoune).
source: wikipedia & google maps