Brazil's Neymar and the $6bn global trade in footballers
The French club paid an eye-watering 222m euros ($260m; £200m) for the player, more than doubling the previous record set when Paul Pogba returned to Manchester United from Juventus for £89m in August 2016.
But that very prominent deal was just the very visible peak of a huge industry, namely the international trade in football players, which is becoming more and more of a global business.
Latest data from Fifa, the sport's governing body, show there have been 15,291 international transfers so far in 2017, with total spending on players hitting a record $6bn (£4.58bn).
International transfers are ones where a player moves from one country to another, as opposed to domestic transfers which take place between two clubs in the same country.
That record figure - which is unlikely to change by the end of the year as player transfer windows in the biggest European leagues are not due to open again until January 2018 - is a 25% increase on the $4.8bn spent in 2016.