Please contact directly the Embassy of France in Colombo: https://lk.ambafrance.org/France-Czech-Republic-bilateral and Dhaka respectively https://bd.ambafrance.org/Applying-for-a-French-visa-in-Bangladesh-2012 to make an appointment for visa submission.

The Embassy of France has full authorization to make decisions on submitted applications as well as to issue visa stickers.   

More information regarding visa processing and rules of entry to the Czech Republic:

https://www.mzv.cz/newdelhi/en/ko/news/partial_resumption_of_visa_agenda_at_the_1.html

https://www.mzv.cz/newdelhi/en/ko/news/rules_of_entry_to_the_czech_republic_for.html