By 9 a.m. local time, a city rent-a-bike network had registered twice as many cyclists - 27,000 instead of the usual 14,000.
Bus, train and subway services in the city were operating at around 10% of their normal capacity with traffic jams reported on all major roads.
Flights in and out of Paris were unaffected, but some travelers had trouble getting to the airport via commuter trains.
The strikers are protesting against President Nicolas Sarkozy's reform plans, specifically the plan to scrap some pension privileges that enable transport workers to retire earlier and on more generous terms.
The government wants to eliminate "special regimes," and create a level playing field for civil servants and private sector workers.
The special funds were introduced for workers in physically demanding jobs, but they are now badly in the red, with a 2007 deficit put at an estimated 5 billion euros ($7 billion).
Transport strikes hit 70 French towns and cities in total.
