This HDR thesis summarizes the professional activities I have conducted this last decade, both before and after I joined Sorbonne. This document is organized into four chapters as follows. The first chapter is my resume, including the list of PhD students I have co-supervized and the past and on-going projects I participated in. The second chapter introduces my research activities, presented into four main scientific themes. This chapter also introduces the people and the fundings involved in this research. The third chapter briefly summarizes the teaching I have done since I joined Sorbonne University and the last chapter presents the research project I intend to carry on for the coming years.