I'll recommend one of my favourite films of all time. However, it's black hole black. I can think of plenty of people who wouldn't agree with the description of comedy no matter how black. Also, it's B&W and Belgian, so if that's a problem for them obviously don't bother with this.
Man Bites Dog
^^I've never seen a poster which puts it forward as a comedy as much as this one does^^
Man Bites Dog
^^I've never seen a poster which puts it forward as a comedy as much as this one does^^
Happiness is another really good choice.