Wearing military battledress, the 46-year-old burst into the 19th-century building and poured petrol around a first-floor room where two women aides to local councillors were working.

"He poured petrol in the room, while the aides managed to get out and cry for help, alerting local police," prefect Jerome Harnois told a press conference.

Officers resorted to "using their firearms several times" after failing to subdue the attacker with a truncheon, Harnois added.

A police source said the man was taken to hospital "in very grave condition", adding that he had no criminal record and his motives were unknown.

Angouleme's mayor Xavier Bonnefont said the fire was quickly put out, while Interior Minister Gerald Darmanin posted on the X social media platform that "no-one was hurt apart from the perpetrator".

Harnois said prosecutors had opened an investigation, adding that the attacker was a French citizen.

"There doesn't seem to be any dispute" between the man and city workers in the town of around 40,000 people, mayor Bonnefont added.

A bomb disposal team checked the attacker's car outside the town hall, an AFP photographer saw.

Police also searched his house in an Angouleme residential district.

One neighbour, a woman who declined to give her name, told local newspaper Charente Libre that the man had recently shaved his head and "wasn't his usual self" when she saw him on Wednesday morning.

"He was angry, he came downstairs like a crazy person (carrying) two cans of spray paint," she added.