Armed police and soldiers will guard French holiday sites popular with tourists this summer following a growing number of terrorist attacks across the Channel.
Britons visiting France will see heightened security at festivals, fairs and beaches, as well as stations and airports.
Backpacks will also be banned on some beaches under new rules.
Cannes council announced on Wednesday that the rucksacks and other large non-transparent bags that could hide bombs would be banned from beaches.
Offenders could be fined or ordered to leave the beach.
The increase in security measures comes after a series of terror attacks in the country, including the murder of a priest in his church on Tuesday.
The Foreign Office’s travel advice warns that there is “a high threat from terrorism” and also said that the French government had reinforced its security measures.
These include a free smartphone app launched by the French government to warn people of possible security incidents, including all major natural, technological and terrorist-related risks.
The app is called SAIP, is available in English and French, and is available free in the Apple app store on Google Play.
The attack came just days after 84 people were killed in Nice as a lorry was driven through the crowd during Bastille Day celebrations. Hundreds more were injured.
France extended its state of emergency following the Nice terror attack.
The state of emergency, which was imposed following the attacks in Paris in November, was due to end on July 26.
The Paris attacks claimed the lives of 129 people after a concert hall, bars, restaurants and a football stadium were targeted.