PARIS — Parisians thronged the sidewalks, took to bikes and scooters or canceled their morning commutes altogether Friday, faced with the biggest public transportation strike in nearly 13 years — a warning shot at President Emmanuel Macron’s government over its ambitious pension overhaul plan.

[Update — France Strikes 2019: Commuters suffer and protests begin.]

Ten out of 14 metro lines were shut, iron gates were pulled tight over many stations, key hubs like the stations at Opéra and Montparnasse were closed. Only the two completely automated lines were fully functional, and huge crowds waited on the platforms of both — the No. 1 line, heavily used by tourists, which cuts through the heart of the city, and the express No. 14, a limited-stop north-south line.

Only one-third of the city’s buses were operating. The suburban trains, known as the R.E.R., were running far below normal rates as well.