The activity of European clubs increased during the last hours of the summer transfer market, which closed its doors at midnight on Thursday.
The most prominent last-minute deals were the signing of Gabonese striker Pierre-Emerick Aubameyang from Barcelona to Chelsea, on a two-year contract.
The Blues also succeeded in attracting Swiss midfielder Denis Zakaria, on loan from Italian Juventus.
Barcelona announced the return of former Arsenal defender Hector Bellerin, who spent a loan period with Real Betis.
The Catalan team abandoned the services of its Danish striker Martin Braithwaite, who moved to local rival Espanyol, and loaned its American defender Sergino Dest to AC Milan.
Portuguese midfielder Andre Gomes joined from Everton, France, on loan.
Liverpool announced the loan of Juventus midfielder Arthur Melo for one season, in a deal that seemed surprising to Reds fans.
Spanish midfielder Carlos Soler has moved from Valencia to Paris Saint-Germain, on a 5-year contract.
On the other hand, Paris Saint-Germain loaned its German midfielder Julian Draxler to Benfica for a season, and also gave up the services of Idrissa Gaye in favor of Everton.