* Deutsche CEO says Europe could benefit from big banks
* BNP's Lemierre says business case needed for mergers
* Cerberus has sparked talk of German bank mergers (Adds Cryan comments on banking consolidation)
FRANKFURT, Nov 17 (Reuters) - BNP Paribas Chairman Jean Lemierre on Friday damped down speculation that France's biggest bank is interested in a tie-up with Germany's Commerzbank.
"We are good friends. But we are friends. Competitors. And we like it," Lemierre said at a banking conference in response to a question.
"No more, no rumor, no comment," he said, while seated next to Commerzbank Chief Executive Martin Zielke.
Several people close to the matter said last month that Commerzbank was working with two investment banks to be prepared in case of a takeover bid from a European rival.
The German government, which still holds a 15.6 percent stake in Commerzbank, has denied a report it favored a merger of the lender with BNP Paribas.
Separately, Italy's UniCredit has recently told Berlin it is interested in eventually merging with Commerzbank, according to people close to the matter.
The investment of U.S. buyout fund Cerberus in both Commerzbank and peer Deutsche Bank has added fuel to speculation that a merger between the two may be on the cards eventually.
Lemierre and Zielke were speaking at a conference of elite bankers that also included Deutsche Bank CEO John Cryan and European Central Bank President Mario Draghi.
A moderator conducted a spot survey of the audience on factors holding back banking mergers and acquisitions in Europe.
Nearly 31 percent, responding via a digital device, said "incompatible financial cultures" were the cause, while 23 percent said "legal fragmentation." Other factors included supervisory obstacles, banks' balance sheets and capital.
Lemierre, responding to the survey, said the most important hurdle to consolidation was missing in the survey: "The business case," he said. "We are business people."
Cryan, whose bank this week saw Cerberus build up a stake of 3 percent and spark talk of banking mergers, said Europe could benefit from a few big banks that could compete with U.S. and Chinese rivals.
"The U.S. and China have very, very large banks which have the heft to invest globally, extend their reach, and withstand relatively long periods of low returns," Cryan said.
"Europe would be well served by having a handful of institutions which could compete on the global stage." (Editing by Adrian Croft and Mark Potter)