Steyn, who has scored 1,201 points for the Bulls in 106 Super matches and 486 points in 42 Tests, rose to prominence in 2009 when he scored a penalty from halfway to win a Test series against the British & Irish Lions.
Steyn's agent Johan van Greune has confirmed that Steyn will be heading to France but insisted his international career is not yet over.
"Morné has spoken to (Springbok coach) Heyneke (Meyer), they have discussed this," he said. "Obviously it is difficult to make commitments from Heyneke's side. That's one of the reasons he chose to go to France. It does open the door for him to play for the Springboks in the future."
However, Steyn has suffered a dip in form of late, leading to Johan Goosen and later Patrick Lambie replacing him in the playmaker role for the national side.
Steyn is the latest South African to move to France after Springbok and Western Stormers left wing Bryan Habana recently ended months of speculation by announcing he had signed a three-year deal with 2012 French Top 14 runners-up Toulon.
Stade Francais, in the lower half of the current French Top 14 championship table with seven wins and seven losses from 15 games, have three South Africans on their books in hooker Michael van Vuuren and locks Gerhard Mostert and Anton van Zyl.