The 26-year-old Uruguay international, Serie A's top scorer last season with 29 goals, has joined Laurent Blanc's expensively assembled Qatari-backed side on a five-year contract.
The previous highest French transfer was set earlier this year, when Colombia forward Radamel Falcao signed for Monaco from Atletico Madrid for a figure estimated at nearly €60m.
"I'd like to thank everyone who made this transfer possible, it's a great project," a delighted Cavani, nicknamed 'the Matador', told a press conference.
"I'd also like to thank the people in Napoli who went out of their way to make it possible," the player who passed the traditional pre-signing medical on Monday, added.
"I come here with lots of joy, lots of confidence, lots of hunger and lots of motivation to win major trophies," he said.
PSG president Nasser Al-Khelaifi paid tribute to the club's outgoing sporting director Leonardo for his instrumental role in securing the services of the Serie A sharp shooter.
"A big thank you to 'Leo', he's done a great job here for the past two years," Al Khelaifi told the press conference to announce the headline deal.
This was the Brazilian's final act in his post before resigning from PSG as a result of the season-long ban he received earlier this month for pushing a referee after PSG's league game against Valenciennes on 5 May.
Leonardo, 43, was pivotal not only in Cavani's arrival at the Parc des Princes but also the capture from Napoli's Serie A rivals AC Milan of Zlatan Ibrahimovic and Thiago Silva.
PSG's previous club record signing was Lucas Moura, the attacking midfielder who joined in January from Sao Paulo in a deal worth a reported €45m.
With former coach Carlo Ancelotti, Leonardo used his Italian contacts to also raid Italy for the likes of goalkeeper Salvatore Sirigu, defensive midfielder Marco Verratti, attacking midfielder Javier Pastore and forward Ezequiel Lavezzi.