(Les) "Années Folles" means "The crazy years" in French.
The saloon robbery in this episode is virtually identical to the robberies in Westworld in "The Original" (season one, episode one) and in Shogun World in "Akani No Mai" (season two, episode five) with one notable difference. The previous two had The Rolling Stones' "Paint it Black" as the instrumental music while this one had Metallica's "Enter Sandman".
When Maeve and Caleb arrive in the newest Delos theme park, the sequence of events, (bumping into the stranger, the children playing with the old man, the wanted poster for Hecky, etc.) is virtually identical to the sequence of events when Teddy arrives in the Westworld theme park in "The Original" (season one, episode one).
As Maeve points out the 1920s themed park bears significant similarities to the westworld park, down to the Butterfly Club, butterfly being a direct translation of mariposa, as in the Mariposa Saloon of season 1.
At 27-28 minutes in, at the beginning of the Butterfly Club robbery, the instrumental music being played is a cover of Metallica's "Enter Sandman".