The Sweden international has ended the speculation by signing a three-year deal with PSG after a fee reported to be 20million euros (£15.7m) was agreed.
The 30-year-old will now link back up with former Milan teammate Thiago Silva, who joined PSG on Saturday.
Ibrahimovic, who had a contract with Milan until June 2015, was Serie A's top scorer last season, netting 28 goals as the Rossoneri finished runners-up to Juventus.
The former Barcelona, Juve, Inter Milan and Ajax striker is the latest big-money signing to arrive in the French capital as PSG bid to win the Ligue 1 title for the first time since 1994 after finishing runners-up behind Montpellier last season.
Earlier this month PSG signed Ezequiel Lavezzi from Napoli with French media suggesting the club paid an estimated 30million euros (£33.5million) for the Argentina forward.
Last summer Les Rouge-et-Bleu signed Argentina playmaker Javier Pastore from Palermo in a deal reportedly worth £37million.
The French club also announced Italian Under-21 international Marco Verratti has signed from Serie A outfit Pescara.
The 19-year-old midfielder, who was called up to Italy's pre-Euro 2012 squad, is highly rated and has signed a five-year contract.
Ibrahimovic joined Milan from Barcelona on loan in 2010 and the move was made permanent the following season. Ibrahimovic was Serie A's top goalscorer last season - a feat he also achieved with Inter Milan in 2009.
The Sweden captain spent three seasons at Inter and two at Juventus, winning the Serie A title every year - although the two he won with Juventus were later revoked because of the match-fixing scandal.