You could spend all day singing the anthemic bits of Les Mis but that would be misguided since it's set in 1815. If you want to get authentically Gallic on La Fête Nationale head for Southwark. Borough Market to Tate Modern will be decked with tricolore and bursting with joie de vivre.
Encounter strolling musicians, street entertainment, theatre, absinthe sampling, free cake - yes, FREE CAKE - other food, drinking, dancing and singing. The traditional waiters' race takes place behind Tate Modern at 5.30pm, there's a French choral evensong in the Cathedral, petanque in Maiden Lane Square, gastronomic films in Southwark Cathedral refectory and a free cultural soiree at the Wapping Project.
Whether you agree that Bankside is 'London's Left Bank' or not, shrug enigmatically and join La Grande Fête from 5.30-11.30pm.
Or go see Les Mis again. Alfie Boe's in it now.
Image by Suke Driver via the Londonist Flickrpool