Ninety police investigators supported by 30 scientific officers and technicians as well as local police are searching for the man, who was seen on security cameras at around 5.30pm on Friday, anti-terrorism prosecutor Remy Heitz told reporters in Paris.

The man was seen leaving a paper bag in front of a bakery. The package exploded about a minute after he left.

French police were able to track the movements of the man, who appeared to be around 30 years old, for 10 minutes before the attack and are still trying to identify him.

The man, who had a bicycle, was wearing sunglasses and a cap.

There has been no claim of responsibility yet for the bomb, Heitz said, calling for witnesses to help police find the suspect.

A source close to the investigation said traces of DNA were isolated from the remnants of the bomb. Police found the attacker used triacetone triperoxide or TATP, a powerful homemade explosive.

The case is being handled as a terrorism investigation given the circumstances of the attack, committed in broad daylight, and the use of an explosive device capable of hitting a large number of people with screws and metal balls packed into a bag, he said.

Police found pieces of a remote detonator and white plastic fragments that were probably part of the device, Heitz said.

Eleven of those wounded in the explosion, including a 10-year-old girl, were hospitalised.

Authorities have boosted surveillance and protection of public areas after Islamist groups carried out a string of attacks around France that killed dozens of people and wounded hundreds in the past few years.

Following the Lyon bomb, the interior ministry called for local authorities to raise surveillance and security in and around public areas and public events all over the country. Army patrols were reinforced in Lyon.

The police chief for the region that includes Lyon banned demonstrations in the northern part of the city.

Australian Associated Press