When the French say that they're doing 'La tournée des grands-ducs', it means that they are going on a classy drinking tour of all the best joints in town. An upmarket pub crawl.
Il ne faut pas mélanger torchons et serviettes. Originally, this proverb has a strong social connotation: tea towels are for the poor and the servants, napkins for the bourgeois and the aristocrats. And one should never mix the two, socially, or otherwise.
Often one sees the 'papis', wearing their berets, sitting in the car park while their wives do the shopping. Women of that generation often don’t drive, so they need a chauffeur. The men don’t often cook either, so they don’t get involved in the buying.