President Francois Hollande will face tough questions on France's faltering economy and a deadly train derailment in an interview with top television channels on Sunday for the Bastille Day holiday.

With the country in mourning after Friday's rail accident near Paris claimed six lives, Hollande will be grilled by journalists from two leading TV channels after attending the traditional military parade for France's main national holiday.

The parade unfolded under a sunny sky in Paris, with fighter jets flying overhead and troops marching down the Champs Elysees to mark the start of the French Revolution, which began with the storming of the Bastille prison on July 14, 1789.

With his popularity at rock-bottom after France fell into recession and unemployment hit record highs, Hollande will be looking to defend his first 14 months in office and to lay the groundwork for difficult reforms ahead.

He will also be keen to reassure the French after the train derailment, which also left dozens injured. Officials said 14 of the injured remained in hospital on Sunday morning, including two in critical condition.

The SNCF state rail company said the accident at Bretigny-sur-Orge was the result of a faulty track and the transport minister complained of under-funding for outdated regional train lines.

Since taking power after his victory over right-winger Nicolas Sarkozy in May last year, Hollande's Socialist government has struggled to meet EU-mandated spending cuts while pushing its agenda of investing in economic growth.

Sources close to Hollande said he would use the half-hour interview at the Elysee Palace to try to convince the French that he is "on the right track and fighting unemployment".

He will highlight a few promising signs that the French economy may be recovering, including a slowdown in the rise in joblessness, the sources said.

Hollande will also touch on tough reforms the government is planning for later this year, including changes to France's pension schemes that have already sparked calls from unions for general strikes.

In a BVA poll released on Friday, respondents said they most wanted to hear from Hollande about unemployment and economic growth, with far less interest in subjects such as immigration, security or foreign affairs.

The Bastille Day military parade, down the Champs Elysees from the Arc de Triomphe, meanwhile drew attention to one of the few Hollande decisions that has won widespread praise.

About 60 troops from Mali and a detachment from the UN peacekeeping force there led the march, joined by French troops who took part in the country's military intervention against Islamist rebels in the west African nation earlier this year.

France's surprise January intervention helped Mali's weak army drive out the Islamists, who had taken over the country's desert north. About 3,200 French troops remain in Mali, as it prepares for the first round of a presidential election on July 28.

In a nod to efforts to cut government spending, officials said this year's march was slightly less grand than in previous years.

The defence ministry said this year's parade budget was reduced by 10-15 percent, with a third fewer vehicles than last year and 12 percent fewer aircraft.

Even with the cuts, about 4,800 servicemen and women took part, along with 265 vehicles, 58 planes and 35 helicopters from the army, navy, air force and other military structures.

Among the aircraft overhead was the new A400M military transport plane built by Airbus, which was unveiled by the European aerospace giant just last month.

Joining Hollande at the ceremony were UN Secretary General Ban Ki-moon, Mali's interim president Dioncounda Traore and Croatian President Ivo Josipovic, whose country became the 28th member of the European Union on July 1.

Hollande was subjected to a few boos and whistles at the start of the parade from a small number of protesters opposed to France's legalisation this year of same-sex marriages and adoptions by homosexual couples.