every step is a headache and this statement is coming to you from a French national returning to France for the first time. It you don't know how the system works, it will drive you nuts. This is from personal experience. Cannot open an bank account because don't have permanent accommodation, can't get accommodation because don't have permanent job, can't find a job because don't have a mobile phone (you need one as you don't have permanent accommodation) etc... Labour laws are so complex here, it makes hiring and firing near impossible for companies are reluctant to take you on. Hélas that is the reality I wish I had known about earlier in the piece.
But don't be discouraged. Many do survive and stay. It is a great experience. Bonne chance.