While some heuristics exist for the learning of graph grammars, few has been done on the theoretical side. Due to complexity issues, the class of graphs has to be restricted: this paper deals with the subclass of plane graphs, which correspond to drawings of planar graphs. This allows us to introduce a new kind of graph grammars, using a face-replacement mechanism. To learn them, we extend recent successful techniques developed for string grammars, and based on a property on target languages: the substitutability property. We show how this property can be extended to plane graph languages and nally state the rst identi cation in the limit result for a class of graph grammars, as far as we know.