Facebook rolled out a new set of five additional Reactions in February, in an apparent response to user feedback. Facebook users had long expressed the need to have a dislike button, but company officials said they didn’t want to bring negativity to the site. Instead, they added five new emojis designed to help users express what they felt: Love, Haha, Wow, Sad, or Angry.

But those emoji reaction buttons are raising privacy concerns in Belgium. Officials say that Facebook is collecting information based on how users react to content on the social network, and selling it to advertisers.

“By limiting the number of icons to six, Facebook is counting on you to express your thoughts more easily so that the algorithms that run in the background are more effective,” Belgium's federal police force posted in a news release Wednesday. “A mouse click can let them know what makes you happy.”

The post continues, “if it appears that you are in a good mood Facebook will infer that you are more susceptible to advertising and will be able to sell advertising space to marketers by telling them they have a better chance to get you to react at certain times.”