From the case-study of two different Tunisian political parties acting in France under Ben Ali’s authoritarian regime (1987–2011) – one of the main opposition party in exile in the 1990s-2000s (the Islamist party, Ennahda) and Ben Ali’s party-state (the Rassemblement Constitutionnel Démocratique, RCD) – this chapter explores the following question: how does the diasporic context shape the possibilities of formation and action for homeland political parties? It argues that what is decisive are the characteristics of both the long arm of the Tunisian regime and the fluctuations of the French national environment, each of which exerted an influence on the possibilities of development of political parties abroad. In a dialectical movement, it looks at what the forms of activism owe to the political environment in which they take place but also what do the groups under scrutiny do to their environment. This chapter shows that some opportunities and constraints are similar across both political parties, some are grouping-specific, which affect in turn each broader political configuration. This strong relationship between the strategies, means of organisation and mobilisation to the context is intrinsically linked to the political parties’ identity and identification.