Hi, I'm French and I have not been able to figure out yet how their website work... When you apply to university straight from France, you get all these information from people you know, etc...

I did all my university studies in Ireland and the UK, and had applied for a Master in Paris after my BA, and it was quite a headache to do as when I was calling them to chack the status of my application, they had no idea in which department they should send me too, in the end I did in the UK.

For PhD, all the people who are successful in their doctoral studies in France generally contact a high-profile French supervisor in their field, try to find contact details, ask info and take it from there. Basically your network is crucial to get in.

I don't know of anyone in architecture though, sorry I can't help more, but best of luck