The European Union (EU) is getting ready for the implementation of СBAM — the world’s first carbon border adjustmentmechanism. This article explores the correlation between intra-European and international facets of СBAM as two sides ofthe same coin: while appending the EU Emissions Trading Scheme, it is equally an instrument of foreign trade, immediatelytouching upon EU relations with trade partners and specialized international organizations. Once such correlation is takeninto account, it becomes evident why the design of the European carbon levy remains capable of improvement as far as fightingclimate change goes.The concept of multilevel governance assists this research as the basis for analyzing СBAM. The institutionalist approachclarifies the specifics of the European carbon border adjustment mechanism. They are important in order to scopeout its true perspective. In particular, the MLG approach helps to expose the blurred lines between market regulation andtax policy in European governance practice.The ways, if any, that СBAM differs from a carbon tax and, at the same time, is similar to a carbon tariff are considered.A reappraisal made in the article of this hybrid measure makes it possible to draw a conclusion that, as envisioned bythe European Commission, it is meant to ensure more favourable conditions for investments in cost-intensive, low-carbontechnologies while suppressing competition from cheaper, high-carbon imports. At the same time, so as to avoid unleashingtrade wars, it is important for the Commission to assure the maximum possible conformity of СBAM to the World TradeOrganization’s (WTO) legal requirements. Compatibility with WTO law would enhance the ecological legitimacy of theregulatory mechanism in question. It would make sure that international partners would not regard СBAM as a form ofgreen protectionism.Further, the subtle aspects of preferences in terms of СBAM design are discussed, as held by the Commission, EUmember states, the European Parliament, and the representatives of European carbon-intensive industries. Particular attentionis paid to the discussion in the EU on the issue of connecting export rebates for inside producers to CBAM.