I am French and I didn't have to do an interview to get the no impediment certificate when I married my Indonesian wife. The only thing is that to get the letter of no impediment, the government needs to release a notice in the French embassy of residence (for us it was Australia) for 3 weeks or so saying that I intend to marry. If no one objects during these 3 weeks, they release the letter. I know, it sounds really backward.
You will only need to do an interview when you register your marriage with the French embassy. They interview both you and your husband separately, asking similar questions and cross checking.