Mr Sarkozy wants to improve the quality of television programming
French viewers have for the first time watched prime-time television without advert breaks, as President Nicolas Sarkozy's media reforms got under way.
Advertising is now banned on French public television between 2000 and 0600. It will be phased out by 2011.
It is part of Mr Sarkozy's move to shake up public broadcasting.
He says his plan will improve the quality of programming but critics say it is a power grab that will deprive state broadcasters of funds.
France Televisions' board of directors chose to back the ban - which affects four main state-funded channels - last month.
It is part of a broadcasting reform package that is currently stalled in parliament.
Mr Sarkozy says the move will allow state-run channels to make better quality programmes because they will no longer have to attract large audiences in order to secure advertising revenue.
The shortfall will be funded through a higher tax on advertisements aired on private channels and a new tax imposed on internet providers and mobile phone operators, the government says.
But critics say the plan will cause job losses and hand funding to private broadcasters - the largest of which, TF1, is owned by a close friend of Mr Sarkozy's.
They are also concerned by another proposal that would give the French president the power to appoint the head of France Televisions, potentially leading to increased government control.
Unions have called for a strike on Wednesday to coincide with the start of Senate debate on the bill.