The latest attack on French prison guards occurred on Tuesday at Tarascon prison in the south of France.
An inmate known to have become radicalized to extremist Islam punched a prison guard in the face, leaving her needing hospital treatment.
While the attack was "not of a terrorist nature", according to reports it will worry prison authorities and guards alike as they continue to protest to demand tighter security at prisons.
The violent attack comes a day after seven officers were injured - three of whom seriously at a jail in Mont-de-Marsan, south west France.
Violence broke out when the inmate, also described as having been radicalized, was being searched by officers after a bag he was carrying set off the alert as he passed through a security gate.
The situation degenerated and the inmate attacked the officers by kicking and punching them. Three guards suffered serious injuries and were taken to hospital.
One suffered a broken nose and another a broken finger. Other officers suffered facial injuries after being punched.
The justice ministry, which put the number of wounded at five, said the inmate, known for being "very violent", was under surveillance "because he was radicalised in prison".
The attack came after guards blocked access to several jails around the country on Monday to demand tighter security after three officers were injured in an attack by a German terror convict last week.
The officers' unions say the blade attack by Christian Ganczarski, who is serving an 18-year sentence over the 2002 bombing of a Tunisian synagogue, illustrated the lax approach of prison authorities to violent convicts.
An anti-terror judge has charged Ganczarski with attempted murder for the attack on the officers, judicial sources told AFP late Monday.
At their protest prison guards used washing machines and a pile of burning tyres to block access to the high-security prison in Vendin-le-Vieil on the border with Belgium where he is being held.
Around 100 officers took part in the protest, an AFP journalist at the scene said.
In an apparent attempt to defuse the situation, the prisons service announced that the director of the facility had asked to be "relieved of his command" following calls by wardens for him to go.
The attacks come as French officials test a range of preventive measures after a string of jihadist attacks over the past two years that have left more
than 240 people dead.
Some of those responsible were involved in Islamist networks in jail. They include Cherif Kouachi, one of the gunmen who attacked satirical magazine
Charlie Hebdo in January 2015, and his friend Amedy Coulibaly, who killed four at a Jewish supermarket two days later.
Dealing with radicalised prisoners and stopping them from converting fellow inmates has been a priority, but the results so far have been mixed.
"De-radicalisation efforts were set up very quickly, and there are lots of gaps," said Esther Benbassa, a senator who recently led a commission on the issue.