Résumé : Norway has used e-voting in its last political election in September 2011, with more than 25 000 voters using the e-voting option. The underlying protocol is a new protocol designed by the ERGO group, involving several actors (a bulletin box but also a receipt generator, a decryption service, and an auditor). Of course, trusting the correctness and security of e-voting protocols is crucial in that context. Formal definitions of properties such as privacy, coercion-resistance or verifiability have been recently proposed, based on equivalence properties. In this paper, we propose a formal analysis of the protocol used in Norway, w.r.t. privacy, consid- ering several corruption scenarios. Part of this study has conducted using the ProVerif tool, on a simplified model.