Microfluidics deals with the management and the control of very small quantities of liquid. At the micronic level, the continuous approach of the fluid mechanics remains valid. However, flows in microfluidic devices open new questions mainly due to the importance of surface versus bulk properties. In this activity, we address the questions of the flow of non miscible or complex fluids in microfluidic devices. The main results are discussed in the two following parts. From the joined lab point of view, these activities are related to the flow of complex fluids in porous media and to the use of microfluidics to enhance the speed of R&D.