 Bloomberg -- Frances contact-tracing app, which the government hopes will prevent a resurgence of Covid-19 as lockdown measures ease, will be available to download on Tuesday. They just have to get people to use it.StopCovid will be available to download at noon in Paris in the Apple Inc. and Android app stores, the government said. Downloading it is voluntary, and it will act as a supplement for human tracers who will manually go through an infected persons contacts.Countries around the world are relying on the apps to help notify people quickly when theyve been exposed to the virus and help prevent a resurgence as offices, restaurants and schools begin to reopen. Still, fewer than half of French people an Odoxa poll for France Info radio said they are ready to download the program.Read more: France Says Virus Recession Will Be Deeper Than ExpectedFrom the first downloads, the app helps avoid contamination, illness and thus deaths, Digital Minister Cedric O said in an interview on France Inter radio on Monday. So there is no minimum threshold for the apps efficiency. Of course, the more people have the app, the better, but there is no threshold to make it efficient. It speeds the tracing process.A University of Oxford study estimated that about 80 of smartphone users need to participate in the program for it to suppress the disease, the equivalent of 56 of the general population. But infections can be reduced significantly even with fewer downloads. One infection can be prevented with every one or two users, it said.O warned on France Inter radio that the virus is still a threat and urged people to use the technology for the collective benefit, as cafes, parks and restaurants reopen with the easing of most lockdown measures on Tuesday.Read More: The World Embraces Contact-Tracing Technology to Fight Covid-19The program is a home-grown solution designed by a state-led task force, including the leading phone carrier Orange SA, software company Dassault Systemes SE, as well as Inria, the institute for research in digital science and technology.The app was approved last week by lawmakers and the privacy watchdog after a debate about how user data, which will be sent to health authorities, will be used and protected.StopCovid will use Bluetooth technology, alerting users if they spend more than 15 minutes within a meter of someone carrying the virus. The French app, which is similar to one being developed in the U.K., is designed by national players, unlike the apps in Switzerland and Germany, which are based on a platform jointly developed by Apple and Alphabet Inc.s Google.For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.2020 Bloomberg L.P. 