For centrists of a certain age, few names are more likely to tug the heartstrings than Emmanuel Macron and Michel Barnier. In the halcyon days of 2017, the two Frenchman seemed the epitome of all that was chic, calm and above all rational: the former a fresh-faced Élysée outsider who made moderation great again; the latter a silver-haired successor to the tradition of Talleyrand as the EU’s Brexit negotiator.