(Recasts lead, adds Gabon arrival, police investigation) By Daniel Flynn DAKAR, July 27 (Reuters) - Nicolas Sarkozy has tried to break the cosy backroom diplomacy of Franco-African ties, calling for more accountability and backing the trial of an ex-Chadian dictator, but his lecturing tone has angered some. On his first visit to sub-Saharan Africa since his election in May, the French president set out his Africa policy at a Dakar university on Thursday, acknowledging colonial ills and calling for democracy, liberty, justice and law. "Cliches, more cliches and still cliches. What an insult!" the Dakar daily Sud Quotidien said on its front page on Friday. "When I heard him talking to students in a hall full to bursting point, I thought of those missionaries who came to Africa to "civilise" our great-grandparents," the article said. Sarkozy jetted on to pay homage to Africa's longest serving leader, Omar Bongo of tiny oil-rich Gabon, a move that raised doubts among diplomats wary of Africa's "dinosaur" leaders. But even as Sarkozy met Bongo, whose French-based assets are the subject of a Paris police investigation over embezzlement accusations, some groups welcomed his break with the past. Sarkozy backed African calls for a bigger role in a reformed U.N. Security Council, saying after meeting Senegal's President Abdoulaye Wade that "Africa must be represented among the permanent members". Sarkozy also pledged financial and legal support to Senegal as it prepares to try former Chadian President Hissene Habre on charges of political killings and torture. "This is a spectacular and welcome reversal of France's traditional silence on this case," Reed Brody of Human Rights Watch told Reuters. "France is obviously a country with great influence both in Senegal and in Chad. It actually supported Hissene, and one of the reasons I think France has always been reticent is because of its support for Hissene Habre," he said. SCEPTICAL YOUTH Sarkozy has pledged a break with France's traditional relations with Africa, marked by personal ties with the ruling elites of its former colonies and dubbed "Francafrique". Yet some Senegalese were unforgiving of France's record and suspicious of Sarkozy's calls for renewed cooperation, which he dubbed "Eurafrica". "France has always been at the side of dirty dictators who have brought Africa to its knees, who have stolen its riches and humiliated its peoples. Will France stop that?" said a university student who gave his name only as Abdoulaye. "Africa's youth cannot change the continent single-handed." Sarkozy has angered many Africans with his policy of limiting immigration to France based on skills and qualifications, which attracted heckling and criticism during previous visits to African countries as interior minister. "What France wants with Africa is an immigration policy negotiated together so that young Africans can be welcomed in France and Europe with dignity and respect," Sarkozy said, urging migrants to return home to put their new skills to use. Thousands of young Senegalese have risked treacherous boat crossings to Spain's Canary Islands in the hope of finding work in Europe, but many of those who survive the crossing end up being packed onto planes and flown straight home. "You'd think he was here to teach schoolchildren. We already know all that. What we want is development plans ... and access to Europe for Africans," said science student Fallou Fall, 20. (Additional reporting by Emmanuel Jarry, Diadie Ba & Alistair Thomson in Dakar and Antoine Lawson in Gabon)