I've always understood that it is mandatory to carry a chart with topographical information. It doesn't have to be a standard ICAO 1:500.000 or sectional chart, you can carry the 1:2.000.000 for legal purposes. It does not have to show detailed airspace information.
I carry the normal VFR charts for several European countries on all flights, even those that are completely IFR (and not V or Z or Y which happens often enough too). But that may just be because I'm a lazy b* and don't want to fuss about where the ** the charts may be.