The Constitutional Court is expected to approve the signatures supporting Melenchon and other candidates later on Friday, the BFMTV broadcaster reported.
In order to be considered for a presidential nomination, French law requires that 500 signatures be collected before March 18 from 30 different departments and overseas collectivities. Additionally, no more than 10 percent of signatures may come from any one department. Mayors, members of the French Parliament and the European Parliament, and special advisers within departments may endorse candidates.
On Wednesday, representative of far-right National Front (FN) party leader Marine Le Pen announced that she had also received the necessary number of signatures.
The French presidential election is scheduled for April 23, while the run-off between the top two candidates is set on May 7.