The former Alternative für Deutschland (AfD) MEP called out the EU boss for proposing to strengthen EU powers over member states.
Mr Kölmel told Sky News: “I think the wishes of Jean-Claude Juncker seems to indicate he wants an ever-closer union. He wants to go step by step and in the end, we will reach an EU superstate.
“I’m sure the people in Europe don’t want to have a new superstate. We want a decentralised EU.”
Mr Juncker proposed plans to make the EU Commission presidency a directly-elected post, thus putting decisional power into the hands of one single man.
He also called for the election of a pan-European finance minister overlooking the economy of member states.

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Express.co.uk revealed that the EU Commission has drawn up proposals for its own version of the National Insurance number, which is used by governments to monitor those who are in work for tax purposes.
The move would hand eurocrats an unprecedented database about people’s earnings and tax affairs and will raise further fears over the growing creep of an EU superstate.
Plans for the new social security scheme are buried at the bottom of a dossier about Jean-Claude Juncker’s proposed new European Labour Authority, unveiled in his State of the Union address.
The authority would be tasked with ensuring a level playing field across the EU in terms of pay and working conditions and is a response to fears of wage undercutting by Eastern European workers.
Tory MEP David Cambell Bannerman told express.co.uk: “Why does a trade block need social security numbers, or an army, or one finance minister, if it isn’t trying to create one superstate?
“Juncker wants control over VAT – already an EU tax – and corporation tax too. Social security numbers mean an EU income tax, national insurance and pensions. This is takeover not trade. We’d better leave faster.”