By Elizabeth Piper and Jean-Baptiste Vey
PARIS (Reuters) - French President Francois Hollande urged Prime Minister Theresa May on Thursday to quickly come up with a negotiating stance for Britain's departure from the European Union but agreed she needed time to trigger the formal divorce.
A day after German Chancellor Angela Merkel also endorsed May's call for some breathing space to prepare for formal talks to end Britain's membership, May won acceptance from Hollande of her position not to trigger the formal exit procedure this year.
But the French leader, under pressure after a deadly Islamist attack in Nice and keen to dampen the popularity of Marine Le Pen's far-right National Front, was clear Britain could not put off invoking Article 50 of the EU's Lisbon Treaty for long.
"The sooner the better," Hollande told a news conference when asked when France wanted to see Britain start the at-least two-year formal procedure to quit the bloc.
"There can be no discussion or pre-negotiation ... but there may be some preparation for this negotiation. We do understand that your government, which has just been formed, needs this time, but again the sooner the better is in the common interest," the Socialist president said.
In her first foreign trips since becoming prime minister last week, May has been keen to lay the ground for what she described as "constructive" talks with the EU's two most powerful leaders as she tries to navigate the unprecedented and complex divorce talks.
With the biggest member states expected to lead the Brexit talks, May has urged France and Germany not to punish Britain and to maintain strong economic ties despite its decision to leave the EU - something she said could not be undone.
"I think it is sensible for us to ensure that the negotiations for Britain leaving the European Union are done in as calm and orderly and constructive a manner as possible and I think that does require some preparation to be made," she said.
"I hope that we can all make the most of the next six months to prepare for these discussions in a constructive way so we maximize the opportunities for both the UK and the EU."
Arriving at the Elysee to members of the palace's republican guard, the new British leader may have been ready for a cool welcome after Hollande, during a trip to Ireland, said May had to justify any foot-dragging over the triggering of Article 50.
But before a dinner of lobster and prawn salad, veal and vegetables, the two leaders said they were looking forward to working together, after Hollande said May had impressed his government on her work as interior minister.
But Hollande suggested it would not be easy.
He, like Merkel, reiterated there could be no formal negotiations on the terms for a post-Brexit Britain before Article 50 and described some of the opt-outs from the EU Britain had already won and the offer made to her predecessor, David Cameron, for a brake on immigration into Britain.
Both said the most testing part of any future negotiation would be Britain's desire to remain part of the EU's lucrative single market, while reducing immigration from the EU.
May, who struggled as interior minister to control migration into Britain, refused to give anything away on how she would balance voters' demands for a reduction in movement with demands from business to keep access to the EU's 500 million consumers.
Described as "utterly intractable" by a Cameron ally, May will be up against not only the equally tough Merkel, but also Hollande, who wants to show the consequences of leaving the bloc to deter Le Pen's National Front push for "Frexit".
Saying he did not want to punish the British people for their decision to leave, Hollande repeated his mantra over a quick divorce. "For France, the sooner the better," he said.
(Additional reporting by Kylie MacLellan and Douglas Busvine in London; editing by Mark Heinrich)