The trick is to keep the relative humidity down, mould can't grow without significant humidity and moisture, some of which comes from the bread, the rest from its surroundings. So some air circulation but not so much that it dries out the bread. Or accept that with decent bread it should be eaten within a day (and a proper French baguette of the type unavailable in Britain, within about ten minutes of purchase). For plastic bagged loaves, I always leave the bag open, plastic bags just make for a sauna.