This paper is about colored object programming. It focuses on a rigorous approach of class inheritance using the color graph formalism. This one abstracts the whole behaviour of a class instances in a N-dimensions space. The paper thus relates a color graph of one class with the color graphs of its superclasses. This is done first at the abstract level of transitions, and then at the implementation level (memory representations are attached to states, pre- and post-methods to transitions), each time by devising and extending the inheritance rules in one given color graph. This work does not depend on the visual formalim itself : it may well be incorporated in state-transition formalisms based on insideness instead of connectedness (i.e. formalisms derived from statecharts).