Bodmer has admitted that injuries and falling down the pecking order in Carlo Ancelotti's midfield made the decision to move on loan easy.
"I needed to play and enjoy my football again," L'Equipe quotes Bodmer as saying. "I was likely to play very little for PSG the rest of the season.
"It is not a risk coming to Saint-Etienne; it is a challenge. I need to get away from Paris for a while.
"The arrival of new players and my injuries all led to my decision to leave on loan."
Bodmer has scored one goal in three appearances since joining Saint-Etienne.