"I don't see what dialogue is possible. The boards are clear on that," he told French daily Le Figaro in an interview published on Thursday.

BNP chairman Michel Pebereau has maintained ever since its bid for SocGen and Paribas was launched in March that he was ready to talk with rival SocGen about the merger plan.

The SocGen and Paribas boards formally rejected BNP's share-swap offers on Tuesday. Bouton repeated in the interview that SocGen and Paribas, which announced plans to merge in February, were ready to strike partnerships with other European institutions, possibly with the potential partners taking equity stakes.

However, he said he was not preparing to bring in a foreign institution to support SocGen in its defence against BNP.

Bouton declined to comment on whether SocGen would raise its bid for Paribas to counterthe approach for Paribas from BNP.

In a separate interview with financial daily Les Echos, Paribas head Andre Levy-Lang, said the idea of giving Paribas shareholders an extra bonus, in the light of greater than expected synergies with SocGen, was "not on the agenda for now".

Bouton also said that while SocGen would not be a direct candidate in the privatisation of Credit Lyonnais, Paribas could well be.

"Paribas, which has developed partnership agreements with the state-owned bank over several years could be (a candidate)," he said.

Paribas, which has a partnership with Lyonnais through its consumer credit unit Cetelem, has long said it wanted to take a stake in Lyonnais. Chairman Jean Peyrelevade was also in favour of Paribas becoming a partner but changed his position after Paribas announced it was merging with SocGen, a direct competitor to Lyonnais in retail banking.