Understanding Parisian Protests (Les Manifs)
Strikes (grèves) and protests (manifestations) are a constitutional right and a national pastime. They are highly organized, heavily policed, and entirely predictable.
The Standard Protest Route
Protests almost never happen near the Eiffel Tower or the Louvre. The traditional protest route runs from Place de la République to Place de la Bastille, or down to Place de la Nation in the east. If you are staying in the 1st through 8th arrondissements, you will likely never see them.
Transport Strikes
When the RATP (Metro) or SNCF (Trains) strike, they must declare it 48 hours in advance by law. Metro Line 1 and Line 14 are fully automated and never stop running during strikes.