The Ligue 1 giants also snapped up the best player at Euro 2020, Gigi Donnarumma, on a free as well as Liverpool star Gini Wijnaldum.
Wijnaldum almost moved to Barcelona as a free agent, with the Blaugrana still snapping up Eric Garcia, Sergio Aguero and Memphis Depay for nothing.
Rivals Real Madrid captured Bayern Munich star David Alaba on a free, while in Italy there was controversy as Inter Milan signed Halan Calhanoglu on a Bosman from cross-town rivals AC Milan.
Below, are the best and most note-worthy free transfers of 2021 so far.
What are the best Premier League free transfers of 2021?
Ryan Bertrand: Southampton to Leicester City
Ashley Young: Inter to Aston Villa
Aaron Lennon: Kayserispor to Burnley
Andros Townsend: Crystal Palace to Everton
Theo Walcott: Everton to Southampton
Danny Rose: Tottenham to Watford
Joshua King: Everton to Watford
Salomon Rondon: DL Pro to Everton
Marcus Bettinelli: Fulham to Chelsea
Wayne Hennessey: Crystal Palace to Burnley
Tom Heaton: Aston Villa to Man Utd
What are the best La Liga free transfers of 2021?
David Alaba: Bayern Munich to Real Madrid
Sergio Aguero: Man City to Barcelona
Memphis Depay: Lyon to Barcelona
Eric Garcia: Man City to Barcelona
Javier Pastore: Roma to Elche
Shkodran Mustafi: Schalke to Levante
Radamel Falcao: Galatasaray to Rayo Vallecano
Axel Werner: Atletico Madrid to Elche
Sergio Escudero: Sevilla to Granada
Aleix Vidal: Sevilla to Espanyol
Carlos Bacca: Villarreal to Sevilla
Marcos Paulo: Fluminense to Atletico Madrid
Marko Dmitrovic: Eibar to Sevilla
Juan Miranda: Barcelona to Real Betis
What are the best Serie A free transfers of 2021?
Hakan Calhanoglu: Milan to Inter
Pedro: Roma to Lazio
Franck Ribery: Fiorentina to Salernitana
Elseid Hysaj: Napoli to Lazio
Antonio Mirante: Free agent to AC Milan
Martin Caceres: Fiorentina to Cagliari
Keita Balde: Monaco to Cagliari
Nikola Maksimovic: Napoli to Genoa
Lorenzo Tonelli: Sampdoria to Empoli
Salvatore Sirigu: Torino to Genoa
Sydney van Hooijdonk: NAC Breda to Bologna
What are the best Bundesliga free transfers of 2021?
Brian Brobbey: Ajax to Leipzig
Jetro Willems: Eintracht Frankfurt to Greuther Furth
Stevan Jovetic: Monaco to Hertha Berlin
Andrey Lunev: Zenit St Petersburg to Bayer Leverkusen
Rafael Santos Borre: River Plate to Eintracht Frankfurt
Omar Richards: Reading to Bayern Munich
Kevin-Prince Boateng: Monza to Hertha Berlin
Mark Uth: Schalke to FC Cologne
What are the best Ligue 1 free transfers of 2021?
Lionel Messi: Barcelona to PSG
Sergio Ramos: Real Madrid to PSG
Gigi Donnarumma: AC Milan to PSG
Gini Wijnaldum: Liverpool to PSG
Jerome Boateng: Bayern to Lyon
Kevin Gameiro: Valencia to Strasbourg
What are the best Rest of the World free transfers of 2021?
Willian: Arsenal to Corinthians
Gigi Buffon: Juventus to Parma
Franco Vazquez: Sevilla to Parma
Victor Moses: Chelsea to Spartak Moscow
Joao Mario: Inter Milan to Benfica
James McCarthy: Crystal Palace to Celtic
John Lundstram: Sheffield Utd to Rangers
Marek Hamsik: IFK Gothenburg to Trabzonspor
Max Meyer: Cologne to Fenerbahce
Troy Deeney: Watford to Birmingham
Gary Cahill: Crystal Palace to Bournemouth
Rodrigo Palacio: Bologna to Brescia
Patrick van Aanholt: Crystal Palace to Galatasaray