There was much criticism of the functioning of this process in the negotiation of the Treaty of Nice in 2001, especially in regard to the Nice European Council which concluded the IGC.
Fungovanie tohto procesu pri rokovaní o Zmluve z Nice v roku 2001 sa dostalo pod paľbu kritiky, hlavne ohľadom zasadnutia Európskej rady v Nice, ktorá zakončila MVK.