Per mcfc.co.uk:

Manchester City Football Club has received notification from the Players' Union (PFA) that it will not support a four-week fine as a penalty for the actions of misconduct of Carlos Tevez.

The Club acknowledges that the Players' Union is the sole organisation empowered with granting the ability for clubs to levy fines greater than the two weeks provided for in player contracts.  

However, Manchester City is disappointed by the apparent PFA conflict of interest evident in this process. Carlos Tevez has been personally represented throughout by the PFA Chief Executive, on whose considerations the Club has been informed that the PFA has made its decision. 

Manchester City has been in constant dialogue with the PFA since September 28th.  Today's PFA decision is a departure from the Club's understanding of that dialogue.

Without recourse to the PFA decision available, the maximum two-week fine provided for in standard player contracts will now be applied in relation to the misconduct of Carlos Tevez.