Revision of the Mileage Allowance
From 1 July 2009, the new amount of the fixed mileage allowance granted to an employee who uses his/her own vehicle (car, motorcycle or moped) to travel on behalf of an employer, will be 0.3026 EUR per kilometer. This amount applies from 1 July 2009 to 30 June 2010.
This new mileage allowance is indeed lower than the one that applied until 30 June 2009, namely 0.3093 EUR per kilometer.
The social security does not qualify such a mileage allowance as remuneration, since it concerns a cost proper to the employer. Consequently, this allowance is not subject to social security contributions. In general, the NSSO (National Social Security Office) takes the amount indicated in the tax rules into account.
http://www.globalemploymentlaw.com/mtc/mt-tb.cgi/239