• the approximate date you saw it: pre 1999
• whether it was in English or another language: I don’t know
• whether you saw it on TV: it is a dubbed movie on TV
• whether it was in color or black and white: maybe black and white
• anything else you can think of that might help pinpoint the film:

I believe it is an old European movie, possibly a comedy.

In one of the scene, A man and a woman (the protagonist) was trapped in a house/building caught on fire.

They find an oxygen tank, and submerge themselves in a bathtub full of water. (taking turn to breath oxygen tank)

The next day, the entire building had burnt out. And the bathtub was only holding up in the air by the pipes.