Facebook's messaging service WhatsApp was ordered by France's privacy watchdog to stop sharing user data with its parent without getting the necessary consent.

The Chair of the National Data Protection Commission (CNIL) issued a formal notice to WhatsApp, criticizing it for "insufficiently" cooperating.

Last year, the European Union privacy authorities said they had "serious concerns" about the sharing of WhatsApp user data for purposes that weren't included in the terms of service and privacy policy when people signed up to the service.

Facebook acquired Whatsapp in 2014. On 25 August 2016, Whatsapp released a new version of its Terms of Service and Privacy Policy, which allowed users' data to be transferred to Facebook in order to be used for targeted advertising, securityand improvement of services.

Following this update, the CNIL asked Whatsapp to stop sharing users ' data with its mother company for advertising purposes.

Whatsapp responded that the data of its 10 Million French Whatsapp users had never been processed for targeted advertising purposes.

However, CNIL says that its investigations found violations of the French Data Protection Act.

The CNIL says it asked Whatsapp to provide a sample of the French users' data transferred to Facebook, but Whatsapp denied it, since it is located in the United States and as such, it is only subject to the legislation of that country.

As a result, the Chair of the CNIL decided to issue formal notice to the Whatsapp to comply with the Data Protection Act within one month.

For the record, the CNIL's formal notices is not a sanction and no further action will be taken if Whatsapp comply with the Act within the specified timescale. Otherwise, CNIL may issue a sanction against the company.