42Consequently, so long as an E 101 certificate is not withdrawn or declared invalid, the competent institution of a Member State in which the self-employed person carries out a work assignment must take account of the fact that that person is already subject to the social security legislation of the Member State in which he is established, and that institution cannot therefore subject the self-employed person in question to its own social security system (Fitzwilliam Executive Search, paragraph 55).
Source: EUR-Lex, © European Union, 1998-2026. Reuse authorised under Decision 2011/833/EU.