The automotive lobby’s voluntary commitment to reducing CO2 emissions in 1998 was widely perceived as evidence of the influence of multinationals on European decision-making. Nongovernmental organizations (NGOs) denounced the lack of transparency. Interviewing negotiators or quoting published reports, scholars focused on the disappointing effects of this agreement. Pending the opening of the public archives, this study is based on primary industry archives, which shed light on the highly confidential negotiation phase. Exchanges within the industry and meetings with the European Commission reveal the limits of the automotive lobby’s power, which had to face internal divisions and seemed to suffer more than choose the agreement. It was the result of Directorate-General (DG) III’s maneuvering. The companies “voluntarily” accepted it as the lesser evil, as it was more advantageous than a directive. The idea of standards being co-constructed by public and private stakeholders needs to be qualified: the balance of power was unbalanced. With these soft regulations, it was above all the Commission that strengthened its position in the decision-making process, to the detriment of other stakeholders such as the European Parliament.