Have you tried the Office des Poursuites?

thanks Anne-Marie. That's actually my next step, but as far as I heard a company can just refuse to pay to OdP and the case is closed. That is why I would I like to predict the 2nd step.

Hi Kris, 

If the debtor refuses to pay during the first step of the enforcement procedure (“poursuite”) by means of an “opposition”, the case is by far not closed. Then however you’ll have to go to court and prove your claim. 

Did you already inform the debtor that you are going to start the enforcement procedure? A reputable business would not like to have such a case mentioned in the publicly accessible enforcement registry and react to your payment request beforehand. 

Regards 

Andre

Dear Andre,

many thanks for your tip. Indeed, I visited today Office de Poursuite, Palais de Justice et Centre de Mediation. They admit that putting a company on the list of "poursuite" can persuade them to pay. I think I'll go with this option, but first, like you proposed, inform the company about what I am planning to do.