PARIS (Reuters) - France’s new COVID-19 contact-tracing app needs to be downloaded by at least 20% of the population to be effective but is far from reaching that level for now, the minister for digital affairs said on Sunday.On Oct. 22, France relaunched its “StopCovid” tracing app and renamed it “Tous Anti-Covid” (all against Covid), which has since seen an additional 1.2 million downloads for a total number of about 4 million. “For the application to be efficient, about 20% of the population, or 15 to 20 million people, need to download it,” Digital Affairs Minister Cedrid O said on franceinfo radio. He said similar apps were working well in Britain, Germany and Canada but gave no examples of successful contact tracing in France with the app. Many in France have been reluctant to download the app over privacy concerns, despite the government’s reassurances that the data will not be used for any other purpose than stopping the pandemic. O said the app would be a crucial tool in preventing the spread of infection once France ends a curfew imposed on two-thirds of the population in an effort to rein in contagion. The app works with bluetooth and warns users if they have been within one metre (3.3 feet) of an infected person for at least 15 minutes.