In the last 20 years, the technique of resonant inelastic X-ray scattering (RIXS) has been progressing at a high pace thanks to the concomitant development of instrumentation, synchrotron technology, and the theoretical description of the related fundamental process. In this article, we describe some recent aspects related to the fast progress of the RIXS technique and dedicate this article to the memory of Prof. Jean-Claude Dousse, from the University of Fribourg (Switzerland). We conclude this article by describing early experiments using time-resolved RIXS at X-ray free electron lasers and give perspectives on high-resolution and spatially-resolved RIXS.