What poses a greater risk to French school children: a potential terror attack, or smoking cigarettes?

This is the unusual question gripping France as a result of the jihadist attacks on Paris last November -- and a court ruling later this week may point to the answer.

Many high schools began letting pupils smoke on school premises as part of security measures introduced after the gun-and-bomb assaults which killed 130 people and left 350 injured.

To education officials, having dozens of teenagers crowd the pavement outside their schools to grab a quick smoke during breaks was simply too much of a risk.

"But this doesn't mean you have to let them smoke inside," complains Corinne Depagne, the mother of a 16-year-old boy, who has filed a criminal complaint against his school in the southeastern city of Lyon.

An administrative court outside Paris is set to rule by the end of this week in a separate complaint against a school in Courbevoie, a northwestern suburb of the capital.

Depagne, a pneumologist, told AFP she was "stupefied" that teens at her son's school were being allowed to smoke in the courtyard between classes.

The official rules are clouded by confusion, and parents, activists and teachers are split between those who think tobacco is the lesser evil, and those who wonder why pupils are allowed to smoke during school hours at all.

Shortly after the November 13 attacks on Paris nightspots and the national stadium, the Islamic State group issued threats against French schools.

Under the state of emergency imposed after the attacks, a circular signed by both the education ministry and interior ministry was sent to schools urging them to avoid having pupils gather outside their premises.

Some schools then sent out letters to parents about new dedicated smoking areas, even specifying that ashtrays would be provided.

- Smoking 'normal' again -

The move outraged anti-tobacco activists such as the group Non-Smokers' Rights (DNF) which argues it is a massive step backwards a decade after smoking was banned in public spaces under the "Evin law," a hard-won piece of legislation named after a former minister of health.

"It is disastrous for public health because we are exposing very young people to tobacco. Many of these establishments are both high schools and secondary schools, with children as young as 11," said Stephen Lequet of the DNF.

"Above all we are making the act of smoking seem normal again."

A study in June 2015 showed that one in three 17-year-olds smoke daily in France.

Lequet said the argument put forward by those in favour of the move -- that it keeps children safe and out of harm's way -- was "false".

"The virtual terrorist risk exists, but luckily it will never leave as many people dead as tobacco," he said.

He pointed out that in other parts of the world, smoking during school hours is completely forbidden, and that as it is even illegal in France to buy cigarettes if you are under 18, the entire situation was "completely absurd".

Lequet said the DNF and other anti-tobacco groups decided to file administrative complaints against three schools in and around Paris, to force them to stop pupils smoking on their premises.

- 'We must remain pragmatic' -

Five months after the circular was issued, the education ministry appears to be struggling to formulate a coherent response to the debate.

Education Minister Najat Vallaud-Belkacem sowed further confusion last week when she said that "during this period of heightened security, high school students must simply be asked not to smoke".

Asked to elaborate on the minister's words, her ministry veered between insisting the measure was "exceptional" but at the same time saying "the ban on smoking must remain the rule."

"According to the minister it is a difficult balance and we must remain pragmatic," a spokeswoman at the education ministry told AFP.

Vallaud-Belkacem's comments outraged the main school principals' union SNPDEN, which said it felt "abandoned" by the education ministry.

"In any case, it is unrealistic," said SNPDEN national secretary Joel Lamois.

"The terrorist risk is much greater right now than the health risk. Between two diseases we are trying to deal with the worst."

- 'Kill themselves smoking' -

But for Depagne that is an outrageous view in a country where 200 people die a day from smoking-related disorders.

"Other parents tell me: 'Why are you pursuing this, Corinne? I don't want them to get killed in front of the school.' I say, 'How can you let them smoke and kill themselves that way?'"

Depagne said the fact that no-one blinks an eye at high school students puffing away outside schools in normal times was a sign of "laxism".

"I think in France addiction is really under-estimated, whether to tobacco or alcohol. It is so normal to smoke that even when children smoke, it doesn't bother anyone."