In this paper we analyze the problem of recognition of temporal expressions and their translations. Starting from named entities describing time (e.g. of the TIMEX type) and using FST cascades, temporal expressions were extracted from a text in French, followed by an analysis of (human) translations of these expressions in several languages, by means of an aligned corpus. The goal of this paper is to develop a formal description of such expressions, which enables the extraction of equivalent temporal expressions from aligned texts