John Nettles: The boy in bleu

France has fallen in love with Midsomer's suave TV detective. John Lichfield investigates

Move over Maigret. Forget Clouseau. The man sitting at a brasserie terrace opposite the Louvre, wearing a British detective's plain blue suit, is one of the most popular flics [cop] in France.

He speaks little French. He has never solved a French crime. He is the epitome of Britishness. And yet, wherever he goes in Paris, John Nettles is recognised – "C'est lui. Regarde. C'est l'Inspecteur Barn-a-bee."

Midsomer Murders is the most popular foreign detective series on French TV. Barnaby, as the show is called by France 3, even has its own fan websites in French.

Nettles was in Paris this week for a round of interviews with the French media. The independent television production company, All3Media, has just sold another Midsomer series to France 3, and the right to rerun some of the old shows in a deal said to be worth more than €1m (£800m).

Chief Inspector Barnaby has, in fact, become the world's favourite British policeman. For four years, Midsomer Murders has been Britain's biggest TV drama export, and has been sold to 230 countries, from Denmark to New Zealand.

I arrested Nettles during his French swing to ask him a few routine questions: "What do the French see in such a quintessentially British series?" And, first: "Is that really a policeman's suit?"

"It is a costume from the series, yes," Nettles says. "It helps to put me in character. But actually, it's Armani. It was the only blue suit that would fit me. I don't suppose many British detectives wear Armani..."

Can he offer clues to the success in France of Midsomer Murders? Would one not expect the French to go for something grittier, not a slow-paced, meandering series full of English eccentrics and rural slaughter?

"I think the series is successful here because it takes the French back to Maigret," he says. "Midsomer is a throwback to the old detective tradition, in which everything happens in the head of one man. Everything depends on his intuition and experience. I think people find that rather restful, as a step back from the more modern TV- detective tradition, which has more violence, more emphasis on scientific evidence. Midsomer Murders is more about character and atmosphere. It portrays a kind of idealised rural England, just as the French like to imagine it" – with cream teas, croquet, dotty spinsters, enthusiastic vicars, and a sprinkling of dead bodies.

Barnaby is especially popular in rural France. My neighbours in Normandy, a retired couple in their sixties, never miss an episode. Francesca Dandolo, series purchase adviser for France 3, says that she believes Barnaby is popular in the French countryside partly because of the landscapes and the English atmosphere. But she points out it also has "family feuds, eccentric people, love affairs – all the characteristics of rural France".

Barnaby is shown on France 3 in late-evening prime time on Sundays, a very tricky slot. The Sunday-evening movie on the leading channel, TF1, is often a recent French or American blockbuster. Watching the "film du dimanche" on TF1 is an institution in France. But Barnaby, in its seventh year there, has been building its audience and now scores 3.2 to 3.6 million viewers, often snatching second place in the Sunday- night ratings.

In the first 23 episodes of Midsomer Murders there were 87 deaths, including 68 murders, the site points out. Aren't French viewers gaining a rather strange view of rural England? And what do the French media make of it? "They want to know whether this is what England outside London is really like," Nettles says. "I don't like to disappoint them, but I have to point out that this is an Agatha Christie England that no longer exists. Take vicars; there are often village vicars in Midsomer Murders, but the village vicar in England was killed off long ago. Sometimes, they ask about the quantity of murders, but I think they accept that's just a fictional convention."

Nettles will admit to a debt to a French actor, Hervé Jolly, who specialises in dubbing. He's the voice of Barnaby, and he has also dubbed Clint Eastwood. While talking in an entirely French accent, Jolly still manages to sound rather like a British policeman. "I've heard him and he is extraordinary. He manages to make me sound like a deep thinker and great intellectual," Nettles says. "Maybe I should send him part of my fee."

'Midsomer Murders' is on ITV on Sunday at 8pm