The Football League did not confirm the size of the penalty, but details of the fine - which has not yet been paid - were disclosed in the club's accounts, which show they made a £38.3m loss in winning the Championship in 2014-15.
That was up from £10.3m the previous season, mainly because of staff wages, which rose to £30.4m, more than double the club's turnover of £12.9m.
Eddie Howe's side won the Championship title last season but exceeded Financial Fair Play limits of permitted maximum losses of £6m for a season.
Championship sides Bolton, Fulham and Nottingham Forest were all placed under a transfer embargo after breaking similar rules.
The accounts also revealed that it cost the Cherries £4.6m to bring their stadium up to Premier League specifications.
Bournemouth were handed a £7.6m fine for breaching Financial Fair Play rules after accruing huge losses last season en route to Premier League promotion.