Geis was a member of the Girona monitoring committee for the 2014 Catalan self-determination referendum (9-N). She was invited by Carles Puigdemont to contest the municipal elections in Girona but declined. However, following the 2017 Catalan independence referendum (1-O), she decided to temporarily suspend her academic career and enter politics. She contested the 2017 regional election as an independent Together for Catalonia (JuntsxCat) electoral alliance candidate in the Province of Girona and was elected to the Parliament of Catalonia. She was re-elected at the 2021 regional election.