TITJUR Rottmann Opinion of Mr Advocate General Poiares Maduro delivered on 30 September 2009. # Janko Rottman v Freistaat Bayern. # Reference for a preliminary ruling: Bundesverwaltungsgericht - Germany. # Citizenship of the Union - Article 17 EC - Nationality of one Member State acquired by birth - Nationality of another Member State acquired by naturalisation - Loss of original nationality by reason of that naturalisation - Loss with retroactive effect of nationality acquired by naturalisation on account of deception practised in that acquisition - Statelessness leading to loss of the status of citizen of the Union. # Case C-135/08.