All euro coins circulate freely in those countries which have adopted the euro as their currency (19 of the 27 EU member states) with a common reverse. Each issuing country can choose its own fixed obverse design, within certain constraints. Additional commemorative obverses are also permitted on 2 euro coins only, but limited to two per country per year for circulating coinage (one per year before 2012) and a maximum 5% of total mintage for that year.
Yours is one of a series issued by Germany commemorating each of its states having Presidency of the Bundesrat (parliament)… in this case Bayern (Bavaria) in 2012.