The theoretical background from which this paper moves is the awareness, which has been raised in feminist scholarship since the ‘80s, of the mutually constitutive character of inequalities. Since Kimberlee Crenshaw coined the term “intersectionality” in 1989, an increasing number of feminist scholars focused on how strategies and policies that address one particular form of discrimination marginalize people who fall in the intersections between different inequalities. The intersectionality theory is a buzzword in feminist theory today, and yet it still needs theoretical elaboration and practical implementation. The first part of the paper addresses what is in a name, why and when was the intersectionality approach was born, what is it for, and how does it work. The second part addresses the legal philosophy differentiation between legal principles and rules as a key for implementing the intersectionality approach through legislation and jurisprudence in civil law systems.