Tourists on the Left Bank this week will come up against the existential burden of individual freedom when they face the quandary of whether it is more Sartrian to drink an overpriced cup of coffee at Les Deux Magots or an equally expensive one at the Café de Flore.

For Parisians, the run-up to Tuesday's 100th anniversary of the birth of Jean-Paul Sartre has provided a more serious worry in the assertion, by some, that the country has run out of intellectuals. The study of Sartre himself, complain academics, has become marginal at university level, and his plays are hardly ever performed in France.

Yet 40 years ago the leading advocate of atheistic existentialism was enough of an irritant for his home in Rue Bonaparte to be blown up by supporters of the French colonial occupation of Algeria. Even shortly before his death in 1980, Sartre went to the Elysée Palace to call for visas for Vietnamese boat people, and was personally received by President Valéry Giscard d'Estaing.

Philosopher André Glucksmann, who accompanied the elderly, blind Sartre to that meeting, says that President Jacques Chirac does not pay much attention to intellectuals these days.

'When Chirac was Mayor of Paris [in the Eighties], I asked him to receive persecuted writer Alexander Solzhenitsyn and he did, because François Mitterrand was President at the time and the French left wing generally considered the Soviet Union to be a good thing. But when a group of us wanted to highlight the case of Commander Massoud in Afghanistan about four months before his assassination in 2001, no one would receive us.'

Glucksmann, one of the spiritual leaders of the May 1968 student rebellion, was one of three prominent French intellectuals - with writer Pascal Bruckner and film-maker Romain Goupil - who supported the invasion of Iraq.

'I do not like the term "intellectual" because no one can agree on what it means,' he said. 'But there are two ways of engaging - either as a prophet of good, in which case you say what people want to hear, or as a sentinel of doom, like me in the case of the war in Iraq. Voltaire was a sentinel of doom - he said what no one wanted to hear - but I don't think it was a typically French thing to do.'

The London-based French writer Daniel Depland looks with desperation at the state of intellectual and creative life across the Channel. 'London is bubbling with ideas and France is asleep. Sartre had intellectual clout but he was also committed. He went and stood at the Métro exits to promote his La Cause du Peuple pamphlet, and his influence was such that Charles de Gaulle did not dare send him to jail.

'French intellectuals today are narcissistic self-publicists with no humility. We're living in an era of entertainment and they are right in the middle of it,' said Depland.

Others in Left Bank circles, such as Grasset publishing director Jean-Paul Enthoven, say the decline of the French intellectual is principally a result of the decline of the Communist party. 'This French habit of taking on the universe is a disease which has been for good and evil. The intellectuals, including Sartre at times, supported totalitarian regimes. Today the intellectuals have become reasonable - Blairite if you like - because we've gone full circle with Marx and we have had Communist ministers.'

Enthoven, 50, is a veteran of the Saint-Germain-des-Prés quarter, the cafés of which originally filled up with literary figures because they were warmer than the writers' flats.

He denies that the area had lost its intellectual edge. 'This is a very pleasant micro-climate of debate and thought. When I go to the United States and hear people still deconstructing Jacques Derrida, I miss Saint-Germain. If anything, the debate is more inspiring here now than it was in the Sixties, when you might have been forced to listen to someone like Louis Aragon blindly defending Stalin.'

French academics say much of Sartre's work has been reduced to a 'detour' for many students. 'We need him to remind us that philosophy is about freedom,' says philosopher Elie During, 'but he has become something of the philosopher for sixth-formers; after the baccalauréat [A levels], students are almost embarrassed to quote him.'

Sartre's popularity also seems in decline in Britain. In the current '20 greatest philosophers' poll being conducted by BBC Radio 4 for Melvyn Bragg's In Our Time series, Karl Marx is in the lead and Sartre is in 13th position.

Nevertheless, his following remains extensive enough for tourists every day in Paris to decide between going to Flore or Les Deux Magots. In the years following the Second World War, Les Deux Magots had silver teapots and was considered too bourgeois by the left-wing intellectuals. Most moved over to Flore, but Sartre and his lifelong companion, Simone de Beauvoir, always treasured the privacy of Les Deux Magots.