* Tear gas fired at Gare du Nord, bins set on fire
* Protests come ahead of bigger event due on Jan. 9
* Widespread public anger over planned pension reforms
* Much of France has been hit by transport strikes (Adds detail and background)
By Sudip Kar-Gupta
PARIS, Jan 4 (Reuters) - Police on Saturday fired tear gas at demonstrators in Paris's busy Gare du Nord station, used by tourists taking the Eurostar service, and at the Gare de l'Est, during demonstrations against plans to reform France's pension system.
The demonstrators, who set fire to rubbish bins, included "Yellow Vests" anti-government activists, whose name is derived from the high-visibility jackets worn at their protests.
Police also used tear gas in Paris's Bastille area, as demonstrators marched through the city.
President Emmanuel Macron has said reforms are essential to simplify the convoluted pensions system, but his opponents say they will mean many French people having to work for longer.
"People have to think a bit about what kind of society they want in general and, on a more personal level, whether you're 20, 30, 40 or 50, one day you'll retire," said Jean-Gabriel Maheo, an industrial technician who said he was in his 50s.
"If the currently proposed system passes in the way it is laid out, it will be a social catastrophe. Already, the previous reforms are seeing people retire with measly pensions," added Maheo, taking part in the Paris demonstration.
Much of France has been crippled by a national transport strike since the pensions protests began a month ago. Another big nationwide demonstration is due on Jan. 9. (Reporting by Sudip Kar-Gupta and Pascale Antonie; additional reporting by Bertrand Boucey; Editing by James Drummond)
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