I'm sorry, the accounting is meant to be public, but I can't find it. It might be too early, or google is failing me.

On a related note, the total budget for the candidates had to be less than 17M€ all included before the first round (then they could spend 5.6M€ more for the second round). A lot of that goes into organizing rallies.

edit: I guess they are meant to be here http://www.cnccfp.fr/index.php?art=584