Paris PJ boss Bernard Petit and his chief of staff, Richard Atlan, were under lock and key on Wednesday, Interior Minister Bernard Cazeneuve announced on Wednsday.
The police force’s internal investigators searched premises for evidence in their inquiry into the alleged leaks, sources told French media.
Cazeneuve promised to come down hard on any member of the police force found not to have “rigorously conformed to the rules that must hold in an administration such as ours”.
Rocancourt was jailed in the US for defrauding stars such as Jean-Claude Van Damme, Mickey Rourke and Michel Polnaref out of thousands of dollars, while posing as a film producer and wrote a best-seller about his exploits.
In France in 2012 he was jailed for swindling director Catherine Breillat out of 650,000 euros and then arrested again in 2014 on various charges, including money-laundering, corruption and impersonating a banker.
A Socialist former junior minister, Kofi Yamgnane, and the founder of the GIGN elite gendarmerie unit, Christian Prouteau, were charged with influence-peddling last October in connection with Rocancourt’s alleged attempts to acquire residency papers for associates of his.
Sources have told the AFP news agency that the suspects are believed to have tipped off Prouteau about impending charges against him.