I will not bother with a plot description of L'Iceberg, since that has been done adequately by a previous reviewer. However, I must disagree with that same person's opinions about the film.
In short it is a very bleak and rather depressing type of comedy. The central character and her family lead a desperately empty existence, which is portrayed well by the bleak cinematography of Belgian suburbia and a dreary port town.
There is precious little dialogue and yet plenty of Belgian-style slapstick interaction between characters. The effect of the film is not uplifting, cheery or even diverting. I have watched many many French-language films - and unfortunately this was the worst I have ever seen.
You have been warned.