An iphone app that gives instant feedback as to how safe a location is has launched in Paris. The BeSafe app, which is also available for London and New York, is currently being downloaded at a rate of 15,000 a week. It assesses the level of security in 80 districts in Paris, according to the time of day, using data from the police.

The 10th, 18th and 19th arondissements are classified as the most dangerous, and the 6th, 7th and 16th the most safe in terms of the risk of theft, pickpocketing or assaults.

Icons let users see hotspots, including the location of gangs, dangerous subway stations and what crimes are being committed. A Risk-o-Meter gauges six levels of insecurity, and calculates the precise level of risk for where the user is. Developers say it is a tool for night owls. Police say the data used is unreliable and not up to date.