Had 3 telephone interviews in french, one with an HR responsible and two with engineers (assosiate and principal). After finding a project that fitted me, they decided to invite me to their headquarters in Paris to meet them personally. Only the date was left to precise. After a week without contact and multiples attemps by me to reach them, they changed their opinion and sent me an email saying that they don't have a project suitable for me. I was left wondering what went wrong.