The attack on prison guards, the fourth in recent days, took place at Borgo jail on the island of Corsica.
Two wardens were hurt when three prisoners charged at them, at least one of whom was armed with a knife. Both were taken to hospital with one suffering a stab wound to the neck.
Initial reports in the French press suggest one of the inmates was a known Islamist extremist.
The inmates linked to the three other recent attacks were also known to have become radicalized raising new fears about how French prison authorities should deal with these dangerous prisoners.
Earlier on Friday French police fired tear gas to break up a picket line of striking prison guards outside Europe's biggest prison as unions pressed a fourth day of strikes across France over security concerns.
The scuffles took place outside the Fleury-Merogis facility just south of Paris as prison guards protested after a string of brutal attacks that have
focused a spotlight on security problems and radicalisation inside often overcrowded French facilities.
Outside the entrance to the prison, which houses more than 4,300 inmates, around 150 striking guards had set up a barricade of burning tyres and wooden pallets to prevent their colleagues from getting to work, an AFP correspondent said.
But a contingent of riot police quickly broke through the picket line, firing tear gas to disperse the demonstrators and allowing those that wanted to work to get inside as the protesters were held behind a police barrier, the correspondent said.
“The CRS (riot police) charged and fired tear gas at us but we tried to resist,” a 28-year-old guard who gave his name only as Sacha told AFP
Litany of complaints
On Thursday, around 120 prisoners had refused to return to their cells after their midday walk in the yard before being brought back in with the help of intervention teams, France's prison administration service said.
Six prisoners who are thought to have led the protest were sent off to the punishment block, a union source said.
Despite talks to resolve the issue that began Tuesday and pledges by President Emmanuel Macron to outline plans for an overhaul of French prisons by the end of February, the unions decided to continue the industrial action.
The strike began on January 11 after a German convict, a former top Al-Qaeda militant, attacked three guards with scissors and a razor blade at a high-security prison in northern France.
On Thursday, guards at more than 123 facilities were “mobilised”, the UFAP-UNSA and the CGT unions said.
Figures provided by the prisons' administration said 87 of the country's 188 detention facilities had been affected to one degree or another by the strike action — around 46 percent.
Union officials have been holding talks with the justice ministry over longstanding complaints by guards of low pay, insufficient staffing and overcrowding at prisons.
Guards now also warn that their safety is at risk following several attacks by inmates linked to Islamic extremism or under surveillance because of the risk of radicalisation.