Claude Simonet stood down a year ago after nearly 11 years in the post.
The inquiry - which followed accusations by auditors charged with looking at the federation's accounts - is expected to be completed within three weeks, but it is yet to determine whether criminal charges will be brought.
According to French sports daily L'Equip, a trading deficit of euros 14.4million was falsely accounted as a euros 62,000 loss for the 2002-03 season.
In the next season, it is alleged that euros 4million was written down to euros 2.6million.
