Europe's data protection watchdog the Article 29 Working Party is now looking into WhatsApp after it said that it would begin sharing user data with its parent company Facebook. The group said it would take proper action.

The Article Working 29 Party Chairwoman Isabelle Falque-Pierrotin said in its letter to WhatsApp that the old users of WhatsApp didn't sign up for the latest update to their privacy policies. "These are not purposes which were included within the Terms of Service and Privacy Policy when existing users signed-up to the service," she said.

Falque-Pierrotin said that they have serious concerns with how the company provided the information about the privacy policy change to its users. They are also questioning the effectiveness of control mechanism that WhatsApp offers to users with regards to exercising their rights.

She adds that the group will act accordingly and take action to clarify the points of concern. Falque-Pierrotin also said they ensure that principles and rights outlined in European and national Data Protection laws are upheld consistently across the EU.

Reuters reports that WhatsApp updated its privacy policy and will start sharing its users' phone numbers with Facebook. This is the first policy change the messaging service underwent since Facebook acquired it in 2014.

A WhatsApp spokeswoman said that they are closely working data protection authorities to address their questions. "We've had constructive conversations, including before our update, and we remain committed to respecting the applicable law," she said.

This is not the first time WhatsApp parent company Facebook has had encounters with Europe's privacy watchdogs. The social media giant had run-ins with these watchdogs in the past over the processing of users' data.

It's hard to see this changing anytime soon, though. The fines that regulators can levy pales in comparison to the big revenues that concerned U.S. tech companies earn.