Studies dealing with EU security and defence policy tend to focus exclusively on what is formally included in the Union’s Common Security and Defence Policy (CSDP). Other initiatives taken outside this framework are frequently seen potentially undermining the development of EU defence – even when the intention is to strengthen defence capacity. This has been the case with the various initiatives taken within or closely linked to the North Atlantic Treaty Organization (NATO), as well as the recent French approach involving the European Intervention Initiative (EI2). An alternative perspective is to see these as integrated parts of a more flexible and differentiated European security framework where all these initiatives combined contribute to strengthening European defence capacity. Building on the argument presented in the introduction to this Special Issue, this article argues that France, as a leader in promoting ‘l’Europe de la défense’, has been instrumental in promoting this differentiated approach to European defence integration, especially under the Macron presidency. (This article is an output of a research project entitled ‘Balancing between integration and autonomy. Understanding the drivers and mechanisms of the EU’s foreign, security and defence policy’ (EUFLEX), funded by the Research Council of Norway (project number 287131) for the period 2018-21.