Five people are in custody after an apparent failed bomb attempt in an upmarket district of Paris.
Police were alerted by a member of the public about suspicious activity in a building in the Porte d'Auteuil neighbourhood on Saturday. Authorities later found and deactivated an explosive device. Two gas cylinders had been discovered in the hallway of the building and two others on the pavement outside. A mobile phone attached to the cylinders was being investigated as a possible detonator, reports suggested.
Police then found the other two cylinders outside the building, believed to be on the quiet Rue Chanez, which runs parallel to Boulevard Exelmans and is a short walk from the Parc des Princes, where Paris football team PSG play their home matches. Reports said the improvised device had been soaked in petrol and was "operational".
An inquiry by counter-terrorism prosecutors is under way following the alert in the affluent 16th district of the French capital.
Interior minister Gerard Collomb said one of those arrested was on a police terror watchlist and had been "radicalised".
It remains a mystery why the bomb was left outside the building on what is a quiet street in one of the French capital's plushest neighbourhoods.
According to French media, police have said there was no one living in the apartment block who might be considered a target for jihadists. But one theory put forward by Le Figaro newspaper is that the bomb makers may have wanted to target an association that battles radical Islam but got the wrong address. This has not been confirmed by any official figure.
France's Interior Minister Gerard Collomb suggested the motivation may simply have been to create fear. "Blowing up a building in a chic neighbourhood shows that no one is safe... it shows that it could happen anywhere in France," the minister told France Inter.