French lawmakers back emergency rule after Nice attack

French lawmakers approved a six-month rollover of emergency rule on Wednesday in the wake of last week's truck attack on the city of Nice, the third deadly assault in 18 months for which the Islamic State militant group has claimed responsibility.

President Francois Hollande's Socialist government remained under pressure, however, over security standards as the head of the regional government in the southern Nice area demanded an inquiry into policing levels on the night of the carnage.

Tunisian Mohamed Lahouaiej Bouhlel drove a truck into crowds of Bastille Day revellers in the July 14 attack in the Riviera coast resort of Nice, killing 84 people before he was shot dead by police. Around 38 of the 84 killed were foreigners.

The extension of extra search-and-arrest powers for police was approved by 489 votes to 26 shortly before dawn in France's National Assembly, the lower house of parliament.

Prime Minister Manuel Valls, jeered by crowds at a remembrance ceremony on Monday and criticised by political opponents over the attack, called for national unity as he presented the emergency rule bill overnight.

"We must remain united and focused because we must be strong in the face of this threat," he said.

"Populism stalks us, ready to pounce at any opportunity, to blow on the embers of discord and exacerbate divisions, as every new division makes us more vulnerable," Valls said.

Valls has accused political foes of unseemly exploitation of events before the dead have been buried. One such opponent, Christian Estrosi, head of the regional government in the area around Nice, renewed charges of serious security failings.

Estrosi said in an interview with the Nice-Matin newspaper Valls and his interior minister had given very different tallies of the number of police officers deployed in Nice on the night of the attack, saying Valls spoke of 185 and Interior Minister Bernard Cazeneuve of just 64.

"Both figures are lies," said Estrosi, who demanded a public inquiry.

In response to demands of the main right-wing opposition party, Les Republicains, the rollover of emergency rule was backed for six months, to late January 2017, rather than the three months proposed by Hollande's government.

The emergency regime, due to be examined by the upper house Senate later on Wednesday before becoming law, allows police to search homes and arrest people without prior consent from judges. It also allows them to tap computer and phone communications more freely.

Emergency rule has been in place since the attacks on Paris last November in which Islamist militants killed 130 people. That attack followed one in January in which gunmen killed journalists working for Charlie Hebdo, a satirical publication targeted over cartoons mocking Islam.