PARIS (Reuters) – A coronavirus contact tracing app being introduced in France may not be able to connect with others across the European Union because it stores data centrally, EU Commission vice-president Margrethe Vestager said on Tuesday.

The EU has been hoping that apps developed by member states to track infections will be able to link up when people move within the bloc, mapping the virus’s spread better and so creating more security for a revival of travel and tourism. Member states agreed technical standards for this on Tuesday.

But France’s approach, which allows central location tracking but has also raised privacy concerns, differs from that of Germany, Italy and others, which log contacts by Bluetooth signal on individual smartphones only.

“It’s somewhat more tricky to develop the technical standards for interoperability between decentralised systems, as I think will be the general rule, and the centralised system that France has been aiming for,” Vestager told the French parliament in a videoconference.

Germany’s app launched on Tuesday, following a standard put in place by Apple and Alphabet’s Google — whose iOS and Android operating systems run 99% of the world’s smartphones.

France has also said that access to its centrally held data is a matter of sovereignty. Its app, “StopCovid”, was launched on June 2 and about 1.5 million people have downloaded and activated it – roughly 2% of the population.

Development of the French app was led by the state research institute Inria, with support from French companies such as the telecoms firm Orange, the IT consulting group Capgemini and the software company Dassault Systèmes.