She reckoned that many of the new members had probably come from the UMP, the mainstream right wing opposition party which is on the verge of collapse.
The party is hoping to benefit from the UMP drama in three upcoming by elections, to be held on 09 and 16 December.
Many UMP sympathisers have expressed their anger at the fratricidal duel between Jean-François Copé and François Fillon over the party leadership, which could destroy the party.
Centre-leaning UMP supporters could decide to join the centre-right UDI party, while those on the right of the party could decide to vote Front National.
François Fillon set up his own parliamentary group, the R-UMP this week, but its adherents retain their UMP party membership.
Copé wants the group disbanded.