Earlier this week, Facebook launched yet another standalone app. It’s called Moments, and it lets friends easily sync photos with each other.

Here’s how product manager Will Ruben describes the app:

“Syncing photos with the Moments app is a private way to give photos to friends and get the photos you didn’t take. Moments groups the photos on your phone based on when they were taken and, using facial recognition technology, which friends are in them. You can then privately sync those photos quickly and easily with specific friends, and they can choose to sync their photos with you as well. Now, you and your friends have all the photos you took together.”

“Moments also keeps all of your synced photos organized and even lets you search them to find the ones that you or specific friends are in. Moments uses facial recognition technology to group your photos based on the friends who are in them. This is the same technology that powers tag suggestions on Facebook. You can control tag suggestions in your Settings.”

Sounds pretty harmless, as long as you don’t have any photos of questionable content to hide. But that whole “facial recognition” thing, well, it’s a sore subject in Europe.

According to Richard Allan, Facebook’s policy head in Europe, it’s this technology that it currently keeping Moments from launching in Europe.

“Regulators have told us we have to offer an opt-in choice to people to do this,” Allan told the Wall Street Journal. “We don’t have an opt-in mechanism so it is turned off until we develop one.”

The spat between European regulators and Facebook over facial recognition goes back years, as Facebook was forced to abandon its “tag suggestion” feature in 2012.

Of course, the feature is alive and well in the States.

According to Allan, there’s no timetable for when the app will launch in Europe. It does seem odd that Facebook wouldn’t have been ready for this, given the history.