Depends on what you call decent and how far from the center you go.
I'm currently outside of Paris, having 15 minutes on foot plus 15 minutes on train plus 15 minutes in Subway to go to work.
I share a large two bedrooms flat (73 square meters) with a friend, and my share is 700€. (this includes water, electricity, heating, garbage collection and unlimited internet connection)
Sure if you insist on having a big flat right inside Paris it may go up to 3k, but if you tolerate commute time you can find better rates.