Paris' bistros and terrace cafes have launched a campaign to be recognized by the United Nations' cultural agency as a French way of life they consider endangered.

Two-and-a-half years after extremists shot at people relaxing in outdoor cafes during the Nov. 13, 2015, attacks, bistro owners have created an association to seek UNESCO "intangible cultural heritage" status.

They said Monday Paris bistros are threatened by increasing rents and competition from lounge bars, fast food and more expensive restaurants -- and their number has halved in the past 20 years.

They argue bistros play a key role in bringing people of all origins, religions, social classes and age together in a cheap, open place to drink a coffee or share a meal.

The association hopes to see its candidacy examined next year by UNESCO.