When is it a good idea to force garbage collection?

So I was reading a question about forcing the C# garbage collector to run where almost every single answer is the same: you can do it, but you shouldn't - except for some very rare cases. Sadly, nobody there elaborates on what are such cases.

Can you tell me in what sort of scenario it is actually a good or reasonable idea to force garbage collection?

I'm not asking for C# specific cases but rather, all programing languages that have a garbage collector. I know that you can't force GC on all languages, like Java, but let's suppose you can.