The 32-year-old did not play a single minute for Arsenal after being stripped of the captaincy in December, and Barca officially announced his arrival on Wednesday.
Arsenal terminated Aubameyang's deal - which was due to run until the summer of 2023 - in order to get his weekly £350k wage off their books, but the Gunners did not do so without taking a financial hit.
According to The Times, Arsenal will be required to fork out £7m to Aubameyang for ripping up his contract, with the Gunners prepared to do so in instalments rather than paying a lump sum.
The former Borussia Dortmund man has penned a three-and-a-half year deal with Barcelona, which possesses a release clause of €100m (£83.3m), and he is believed to have taken a significant pay cut in order to move to Catalonia.
Aubameyang left Arsenal after banking 92 goals in 163 appearances for the North London club, winning the FA Cup and Community Shield during his four years at the Emirates Stadium.