In this paper, we discuss the theoretical, sociolinguistic, methodological and technical objectives and issues of the French Creagest Project (2007-2012) in setting up, documenting and annotating a large corpus of adult and child French Sign Language (LSF) and of natural gestural language. The main objective of this ANR-funded research project is to set up a collaborative web-based platform for the study of semiogenesis in LSF (French Sign Language), i.e. the study of emerging structures and signs, be they used by Deaf adult signers, Deaf children, or even by Deaf and hearing subjects in interaction. In section 2, we address theoretical and practical issues, emphasizing the outstanding features of the Creagest Project. In section 3, we deal with methodological issues for data collection. Finally, in section 4, we examine technical aspects of LSF video data editing and corpus annotation, in the perspective of setting up a corpus-based formalized description of LSF.