For over a year now, a French law has provided a means for law enforcement to block stolen phones and prevent them from being used. French mobile phone users are encouraged to record their IMEI number online with authorities as a precautionary measure. Once a phone is reported as stolen to the police, operators are required to transmit the unique IMEI number on each phone to a European bank in Dublin, Ireland. Then, this bank is supposed to block usage of that phone, rendering it unusable.

The French newspaper Le Monde (Google Translate) reports that mobile theft in France has dropped 20 percent between April 2011 and April 2012, suggesting that this measure has been somewhat effective.

However, the Paris police department has now announced that it has discovered the use of software called Z3X, which has apparently been found in 50 mobile phone shops in eastern Paris. Z3X is a Ukrainian-made tool that offers what appears to be a specific way to reset IMEI numbers on various specific phones, including models of Samsung, LG, NEC and other phones. The group has listed resellers scattered across the United States, Europe, Russia, Ukraine, and Libya.

The software apparently allows the IMEI number on the phone to be reprogrammed, which under French law, according to a French police source speaking to Le Monde, is punishable by up to two years in prison and a €37,500 ($46,000) fine.

Not surprisingly, these reprogrammed phones end up back on Parisian and French streets. The newspaper also reports that the French Ministry of the Interior and the French Federation of Telecoms have been looking into how to deal with this new software.

“We would like there to be a synthetic engraving of the mobile IMEI number directly on the phone,” said Frank Carabin, a Paris police spokesperson, according to Le Monde. “We would ultimately like manufacturers to put in place a device that would remotely make phones unusable when stolen,” he added. “We need to quickly find a solution.”