The celebration of Bastille Day isn't actually expounded in the film. It's almost assumed that the French day of revolution is known to the general public as Christmas or Valentines. No worries about having no frame of reference as one will find out later from the plot.
A bomb mule and a pickpocket are in over their heads when they are unwittingly involved in a terrorist attack. Or are they? Unruly agent Briar is on the case, unraveling the clues by dodging both the French authorities and American representatives.
The film isn't exactly what it seems but more of what one thinks is a revolution is. It really is more of a smaller affair of sorts. It's still a good action flick but expectations might be raised due to the supposed political theme, which there really isn't much of.
Idris Elba carries himself well as a rough and tough lone wolf and Richard Madden is good as a skillful but hapless thief yet they don't really work close enough together to build a buddy bond. They also stage a chase scene that could have been a great parkour exhibition if they tried hard enough. The lady Charlotte Le Bon was good as the naive revolutionary but varies on the fire she's suppose to display.
Bastille Day could have been bigger but the plot doesn't require it to be. It could have aimed higher but as it is, it's a decent cop action flick and a pretty good showcase of Idris Elba as an action star.