How did the theory and practice of computing interact to generate a new discipline, computer science? Studying the French scene, in comparison with other countries, reveals that in most cases computing developed initially as an ancillary technique of applied mathematics, with little awareness of the path-breaking theories of computability elaborated in the 1930s. This was particularly clear in France, where mathematical logic was almost inexistent and disregarded by the Bourbaki group.It was only in the early 1960s that researchers in the emerging field of computing felt the need for theoretical models, and discovered the Turing machine and recursive functions. Simultaneously, an interest for language theories and information structures, fostered by practical projects such as machine translation, converged with issues raised by software development and the nascent theory of automata.The convergence of these diverse intellectual agenda was central in the process of construction of the new discipline.