NICE, France (Reuters) - Three months after a man plowed his truck into crowds on France's national day in Nice, the southern coastal city is trying to recover as it prepares to remember the 86 victims in a national ceremony of remembrance.

Tributes line the sea-front promenade along which Tunisian-born Mohamed Lahouaiej Bouhlel drove a 19-ton truck, mowing down people watching fireworks on France's July 14 Bastille Day, before police shot him dead.

Curious visitors and grieving locals stop to look at bouquets of flowers, toys and yellowing notes left in memory of the victims.

"We haven't forgotten it. People are less trusting, more nervous and the atmosphere is heavier," said Stephanie Marton, a mother of five who was on the promenade with her children that night. "(It) is not at all like what it was before July 14."

Marton said the family, who threw themselves onto the ground out of the way of the truck hurtling toward them, still lives in the shadow of the attack.

"Three months later, it's still in their heads and it's still hard for them," she said. "They still have nightmares at night - and I sometimes get them too - and they find it really hard to be near the promenade."

Nice was due to hold a national ceremony of remembrance, led by French President Francois Hollande, on Friday, exactly three months after the attack.

But a statement from his Elysee Palace on Thursday said the event, on a hill overlooking the French Riviera and attended by survivors and victims' families, will now take place on Saturday due to bad weather.

(Reporting by Michel Bernouin; Writing by Johnny Cotton and Marie-Louise Gumuchian; Editing by Tom Heneghan)