None. As a former Hungarian diplomat, Tibor Kiss is not subject to the EU revolving door rules.
PA Europe says "More than ever before PA Europe provides access and advice to European top level decision makers in Brussels and national capitals and develops tailor-made approaches for its clients on the basis of solid research and strategic analysis." http://www.pa-europe.com/pa_europe/aboutus.htm
“[Ambassador Kiss] was instrumental in Hungary's successful accession to the EU and its preparations for hosting the EU Presidency in 2011. As such, he headed and managed the largest representation of Hungary abroad and acquired a profound insight into EU policies and institutions, including the challenges of inter-institutional cooperation, political communication and counselling”. (Source: European Agenda)
More information from: http://www.pa-europe.com/pa_europe/News_TiborKiss.htm
"Ambassador Kiss is one of several ambassadors or senior diplomats who have recently gone through the Brussels revolving door and who have now joined a lobby consultancy; PA Europe appears to pride itself on recruiting former prime ministers and ministers from the EU member states. CEO considers that this job move provokes the risk of conflicts of interest. As PA Europe's chairman says (himself a former Belgian Prime Minister): “Through his work in Council and Coreper Ambassador Kiss knows the main dossiers, the leading persons as well as the national and institutional stakeholders’ positions. His personal insights and profound knowledge of the way Brussels works will be a great asset to PA and its clients”.