* French presidential hopeful Macron campaigns in London * Meets British PM May, sticks to firm stance on Brexit * Polls suggest Macron's momentum fading * Big cheers for EU at rally for French nationals By Estelle Shirbon LONDON, Feb 22 (Reuters) French presidential candidate Emmanuel Macron told British Prime Minister Theresa May not to expect any favours from the European Union during Brexit talks, and drew big cheers for his pro-EU message from French nationals in London. Macron visited May at her Downing Street office and later met Britain's finance minister Philip Hammond, a public relations coup for the young ex-banker at a time when his campaign appears to be losing momentum. "Brexit cannot lead to a kind of optimisation of Britain's relationship with the rest of Europe. An exit is an exit," he told reporters outside 10 Downing Street after meeting May. "I am very determined that there will be no undue advantages." Macron, 39, a former economy minister in Socialist President Francois Hollande's government, is running as an independent. He is due to unveil his detailed programme next week. The latest polls suggest he and right-wing rival Francois Fillon are tied behind far-right leader Marine Le Pen ahead of the first round of the election on April 23. Polls suggest either man would easily beat Le Pen in the May 7 run-off. Macron, who did not obtain a meeting with German Chancellor Angela Merkel during a recent visit to Berlin, was keen to improve his standing on the world stage and court voters in London, which has an estimated 200,000 French residents. At his campaign rally, in a packed hall where people waved French and EU flags, Macron drew the biggest cheers when he spoke in favour of the European project. "Our country cannot succeed without Europe," he said. He advocated a "special relationship" between the EU and France on the one hand and Britain on the other. The term is more commonly used in Britain to describe ties with the United States. "Nothing will be the same (after Brexit), but I think we can defend mutual interests over the long term," he said, citing close cooperation between London and Paris on defence and security. He suggested he would seek to partially renegotiate the Le Touquet agreement, which allows France and Britain to have border controls on each other's territory, so that London would contribute more to managing the issue of refugees and migrants who gather in Calais in northern France to seek ways to Britain. Macron said he and May had discussed what would happen to French expatriates in London after Brexit. He said he wanted them to be free to continue their lives in Britain if they so wished. But he also said that he was fed up with hearing about young French entrepreneurs who felt they could not succeed in France and moved to London because it was easier to start a business there. He said his ambition as president was to make France more attractive so such people would stay, or return. REUTERS SDR 0805