Hi Nikos,
I do not know about a store with French groceries in Amsterdam but I do not know of a great French baker in The Hague. He is traiteur too.
Michel (name of bakery)
Jan van der Heijdenstraat 31
2522 EL Den Haag
Tuesday till Friday: 7h to 18h30
Saturday 7h to 16h30
Sunday 7h à 13h30
Oude molstraat 17
2513 BB Den Haag
:
Tuesday till Friday: 8h30 à 18h30
Saturday 8h30 till 17h
Sunday 8h30 à 13h30
There is a new shipping company where you can order genuine French products to the Netherlands but instructions are all in French http://www.lafranceadomicile.com
Le fournil (The one that you recommended) has an excellent reputation among French expats in The Netherlands. I know that quite a few French people dream of such a bakery closer to them! Ah baguettes and croissants, pastries once in a while...
Let me know if you do find one, I will know to check it out next time I come to Amsterdam!
Lucie