We still do not understand how planets form, or why extra-solar planetary systems are so different from our own solar system. Recent observations of protoplanetary discs have revealed rings and gaps, spirals and asymmetries. These features have been interpreted as signatures of newborn protoplanets, but the exact origin is unknown, and remained until recently poorly constrained by direct observation. In this talk, I will show how high spatial and spectral resolution ALMA observations can be used to detect embedded planet in their discs, and discuss the implications on our understanding of planet formation.