If Man City are found guilty of the FFP charges, They'd be relegated from the Premier league. That's a big iff though, since it's Man City, they will lawyer up and just throw more money at the problem.
Of course it is true, Manchester City will receive severe punishment if they are proven to have violated the rules. However, to this day, they have not been found guilty even though there are more than a hundred accusations that have been filed. Other rivals including Liverpool and Arsenal would certainly love for Manchester City to get punished, but so far there have been too many rumors to be believed.
I hope Manchester City is truly able to defend itself against all these accusations and win the trial. This is what all their fans hope for, especially because this season Manchester City has a big chance of defending its title for the fourth time in a row.