Thanks for your insightful vision.
Even tho I don't have much experience in double basses I kinda had a feeling the wood didn't look 'right'.
What troubles me is that it has a bridge by Noël Warnier, he is a respected/experienced luthier over here (
http://noel.warnier.free.fr/luthier/spip.php?article1).
I ask myself, why would somebody ask someone like him to cut him a (probably expensive) bridge for a crappy fake bass and on the other hand why would someone with his reputation get involved in this.
I just mailed the seller to ask him to take a photo of the builders label. A fake label will probably be easily reconcognizable.