As Webster 1913 says below, the word "fire" derives from the same root as German "feuer". The French word for "fire" is "feu", but Ferdinand de Saussure notes in his Cours de Linguistique Générale that there is no common origin with the German word although they look very close. The French "feu" derives from the Latin "focus".

This could be a mere coincidence. After all, there are many words in the language, and few different sounds, owing to double articulation.

So, is this is a case of cross-cultural sound symbolism? Do all the cultures in the world associate the sound "f" with the crackling and humming flames in our parents' chimney?

(thanks Shro0m)