The proposed law has been put forward by socialist senator Yannik Vaugrenard who is backed by anti smoking groups who successfully lobbied for a ban on smoking in enclosed public places in 2006.
The initiative follows a recent study published in the Tobacco Control Journal which says that smoking in cars exposes passengers to three time the toxin levels considered safe by the World Health Organisation and that opening the car windows makes no difference.
Anti-smoking group Droits des non-fumeurs admits a ban may prove difficult to enforce and recommends a publicity campaign to remind parents of the dangers.
The CAF (Caisses d'Allocations Familiales) needs to make €2.2billion worth of saving to balance its books and the shortfall is expected to rise to some €1.7 over the next three years.
Abortion and contraception for minors are to be free from the end of this month.
Health minister Marisol Touraine last week announced that abortion will be 100% reimbursed for all women from March 31 and contraception free for girls aged between 15 and 18.
Peillon, who believes that six weeks is long enough for a summer holiday, wants to move towards a cycle of seven week terms broken by two week holidays. He also supports the zoning of the summer holidays by region - as is already the case for other school holidays.
His priority, however, is to lengthen the school week, a move broadly supported by teachers and parents but opposed by teaching unions.
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