Problem with tabel of content : no entry appears

Hello,
I’ve a very simple problem, but I spent too much time for it so I decided to ask.

I applied some paragraph styles (Heading 1 and Heading 2) in my document. Now I just want to make a simple table of content up to level 2.

I inserted it, I defined the paragraph style for level 1 and 2 (Heading 1 and Heading 2). But there is no entry, just the title. Updating the table doesn’t work either.

It is so basic but yet I can’t find any way to make it work !
Did I miss something ?

Make use, that in Tools > Outline numbering the paragraph styles are correctly assigned to its level.