The area where the explosion occurred, on the narrow strip of land between the Saone and Rhone rivers in the historic city centre, has been evacuated, according to AFP journalists at the scene.

Police have released this CCTV footage of the man they want to speak to

According to reports in the French press a man was seen arriving in the area on a bike before leaving some kind of package or suitcase at the scene. The man has not been arrested and is the subject of a police manhunt.

A police source told AFP the package contained “screws or bolts” and had been placed in front of a bakery on the corner of the two popular streets.

Police said that none of the injuries appear to be life-threatening.

President Emmanuel Macron called the blast an “attack” during a live Facebook interview, adding that no deaths had been reported “for the time being.”

“It's not for me to give a toll but it appears there are no casualties. There have been injuries, so obviously I'm thinking of these injured and their families,” Macron said

“An eight-year-old girl was wounded…. We're fairly relieved because apparently there were no serious injuries but on the other hand, we are certain it was an explosive device,” said Denis Broliquier, mayor of the city's Second Arrondissement.

He said the suspect sought by police had been seen on video surveillance cameras.

“There was an explosion and I thought it was a car crash,” said Eva, a 17-year-old student who was about 15 metres (50 feet) from the site of the blast.

“There were bits of electric wire near me, and batteries and bits of cardboard and plastic. The windows were blown out,” he said.

A terrorism probe has been opened by the Paris prosecutor's office, which has jurisdiction over all terror cases in the country.

France has been on high alert following a wave of deadly jihadist terror attacks since 2015 which have killed more than 250 people.

“It's an area in the very centre of Lyon, a major street,” the city's deputy mayor in charge of security, Jean-Yves Secheresse, told BFM television.

“These areas are highly secured, the police are continually present,” as were patrols by soldiers deployed in a long-running anti-terror operation, he said.

A planned concert by British singer Ed Sheeran went ahead in Lyon, albeit with heightened security.