When someone calls the fire service, vital time can be lost while first aid services are getting to the victim. The first four minutes are vital.
After that time, it is estimated that for every minute, the chance of survival decreases by 10%.
After 10 minutes without resuscitation, the prognosis can be fatal. Every year, 50,000 people die in France from a heart attack – or about 137 a day.
The Staying Alive app was created by the French organisation AEDMAP, in Boulogne-Billancourt, near Paris.
People with a basic first aid certificate can sign up as a bon samaritain (citizen responder).
If they are near to an incident, fire services will contact them to go and start resuscitation.
If there is a second person nearby, they will be called to fetch the nearest defibrillator.
Laurent Istria, business development manager for Bon Samaritain, said: “It is used by fire brigades in 35 departments and there are about 10 more ready to sign up; 75,000 people have signed up to be a citizen responder.
“One third are qualified firemen, one third are medical professionals and one third are the general public.
“They can show they have a qualification by uploading their certificate on the app.
“The most basic French certificate, Gestes Qui Sauvent, is all that is necessary. This you can do from 10 years old. “It takes a couple of hours to learn and costs about €15 (Red Cross price).
“It will teach you heart massage and how to use a defibrillator.”
Since the beginning of 2018, more than 3,000 citizen responders have been called to an emergency and Mr Istria is now touring the country to persuade other fire services to use the app.
You can also put your name down as a citizen responder without qualifications, and in that case could be called on to fetch a defibrillator. The app will show you where you can get first aid training near you.
Citizen responder is an addition to the Staying Alive app, which was created 10 years ago to give the location of defibrillators around the world.
More than 160,000 are listed on the app, which has been translated into 18 languages.
Users can add any others they find on their travels.
The Good Samaritan element was developed after a doctor said it would also be useful to have a list of people who could help out in the event of a heart attack.
Mr Istria said the app is free to both the public and fire services because AEDMAP is a foundation funded by sponsors from the medical, health insurance and banking world.
The Fédération National des Sapeurs-Pompiers de France became an official partner in June.