He confirmed that he's coming to Arsenal to a French TV station after the match yesterday.

http://metro.co.uk/2014/07/05/mathie...nsfer-4787604/

‘Yes, I will be joining Arsenal for next season,’ he told a reporter from TF1 television following France’s World Cup exit to Germany.
7.9 million is the fee.

Anyway, welcome Mathieu.

We may have had some doubts over his value but now that's he's our player (all but), it's time to support the guy 100% and defend him against naysayers.