Bastille day as its knows in English is celebrated by France and its former colonies, with occasional appearances from allied countries (eg. U.S and UK)

​Short Answer: France

Where Is It Celebrated

During the french revolution (1789-1799) a castle known as "The Bastille" was being used as a prison by the french government was under siege by the revolutionaries finally fell on July 14 and that marked a turning point in the revolution

Why Bastille Day Is Celebrated

There aren't many sayings for La Fête National, but bonne fête nationale and Joyeux Quatorze Juillet. There are definitely ways to not say it. If you were to say "Le Jour De Bastille" no native French speaker would know what you're saying. Other vocabulary is défilé militaire (military parade), La Révolution Française (The French Revolution), and Vive la France! (Long Live France)!

Wishes for Bastille Day