French does not have a continuous form in the way that English does. In fact, "Les hommes lisent" corresponds to both "The men read' and "The men are reading", and French speakers do not usually feel the need to distinguish between the two concepts. If you really want to emphasise the fact that they are in the process of reading something at the moment, you could use the expression "Les hommes sont en train de lire", but this is not used as frequently as English uses the continuous form.