Pope Francis issued an Easter proclamation that said "we are all racists". I trust that this is the catholic "we". After reading this, I wondered whatever happened to Pope Benedict, recall that he had resigned, "citing a "lack of strength of mind and body" due to his advanced age. His resignation became effective on 28 February 2013. He is the first pope to resign since Gregory XII in 1415, and the first to do so on his own initiative since Celestine V in 1294."
I guess that retirement suited him as he is now 93 years old and the longest-lived Pope ever.
To answer my question, according to the media he lives in a monastery inside Vatican City. Wikipedia tells us that Pope Francis took over Benedict's twitter account upon his ascension to the Papacy.