The versatile playmaker signed for Japanese club Shizuoka Blue Revs from the Lions in 2024, but only made five appearances off the bench in two seasons as injuries hampered his career.
Nohamba last ran out for the Japan League One side in January, then revealed in May that he was leaving the club.
The 27-year-old - who is equally at home at scrumhalf or flyhalf - has now been picked up by Lyon.
"LOU Rugby is delighted to announce the signing of scrumhalf Sanele Nohamba from the Shizuoka Blue Revs on a two-season deal!" read their social media.
"The 27-year-old South African, who previously played for the Lions and was named the URC Player of the Season in 2024, will add valuable depth to the squad. His quality and experience will strengthen the Red and Blacks as they compete in both competitions over the next two seasons."
Defending champions Griquas and the Lions both bounced back from opening-round defeats with emphatic bonus-point victories in the Currie Cup on Saturday, hammering the Bulls and the Pumas respectively.
The Lions are back at Ellis Park this Saturday for their Round 2 Currie Cup encounter against the Pumas.
Mads Bidstrup has completed a move to Olympique Lyonnais after ending a successful three-year spell with Red Bull Salzburg.
Ivan van Rooyen and Sacha Feinberg-Mngomezulu have added their names to the United Rugby Championship Awards roll of honour by collecting the Coach of the Season and Players' Player of the Season titles.
