Robinho is set to leave City this week for a return to Brazil on-loan.
Sao Paulo director Carlos Augusto de Barros e Silva said: "We were approached from over in England saying (City) manager Roberto Mancini would like Robinho to play for Sao Paulo because the club have greater international reach and will play in the Copa Libertadores.
"That, according to him, would promote a greater revaluation of the player which is exactly what they want.
"From there, Sao Paulo became interested. We have had a representative in Manchester since Saturday looking after this issue.
"I've only got the exchange of emails with the businessmen. In money terms, I think the best thing for him (Robinho) is Santos."
Eastlands technical director Mike Rigg visited the club's impressive training base last year as part of a trip to Brazil with Luis Vicente, a Portuguese lawyer who is City's "head of partnerships".
Robinho also turned to Sao Paulo in March, preferring to make a 10,000-mile round trip for treatment on his ankle from the club's physio Luiz Rosan rather than utilising City's backroom staff.