A French-African summit opens here today overshadowed by protests against the presence of President Robert Mugabe of Zimbabwe and by the decision of Ivory Coast's president, Laurent Gbagbo, to stay away.

The summit is being attended by heads of state and representatives from 52 African countries; only Somalia, which has no recognized government, was not invited.

But the efforts of French President Jacques Chirac to win influence across the continent -- not just in France's former African empire -- carried the price of protests against Mugabe.

The Zimbabwean leader's invitation also sparked a diplomatic dispute between Britain and France over European Union sanctions against Zimbabwe.

Mugabe is under fire from Western countries that have imposed travel and economic sanctions since his reelection a year ago in what they say was a flawed vote.

Mugabe has accused Britain and other countries of "neo-colonialism" in southern Africa when they criticize, among other issues, the forced transfer of land from white farmers to landless blacks.

France asked the EU to allow Mugabe to travel to the two-day summit and got its way despite objections from Britain, the former colonial power.

A British human rights activist, Peter Tatchell, staged an anti-Mugabe protest in front of the French Justice Ministry, where demonstrators waved banners saying: "Arrest Mugabe for Torture."

"It's a disgrace," said Tom Spicer of Zimbabwe's main opposition Movement for Democratic Change, who said he was tortured by Zimbabwean police last year. "Mugabe should be ostracized from the international community."

Ten protesters from the gay rights group ACT UP were arrested in front of Mugabe's hotel, a police spokesman said. Mugabe has likened homosexuals to dogs. Four journalists were briefly detained.

French Cooperation Minister Pierre-Andre Wiltzer, who deals with overseas aid, defended inviting Mugabe to the summit, saying it would be a platform to engage him on human rights issues.

"When you have things to say, you should say them to each other face to face," Wiltzer said.

Hopes that the summit would tackle a five-month-old uprising in Ivory Coast dimmed after Gbagbo declined to attend, in a clear snub to the former colonial power.

Gbagbo's adviser in Paris, Toussaint Alain, said Ivorians were "shocked and outraged" at what he called France's lack of clear commitment to Gbagbo and soft stance in dealing with rebels who hold at least half of the cocoa-producing state. France has dispatched 3,000 troops to Ivory Coast.