“The duty of ‘sincere cooperation’ set out in Article 4(3) TEU requires Member States to take appropriate measures to ‘ensure fulfillment of the obligations arising out of the Treaties or resulting from the acts of the institutions of the Union’ as well as to ‘refrain from any measure which could jeopardise the attainment of the Union’s objectives’. When and in what way are Member State authorities required to act – or desist from acting – in order to comply with this duty?”
Competition Bulletin from Blackstone Chambers, 16th January 2013
Source: www.competitionbulletin.com