PARIS, Oct 19 (Reuters) - Striking public sector workers disrupted travel across France on Tuesday and sporadic violence flared at protest marches as opponents of President Nicolas Sarkozy's pension reform made a last-ditch attempt to stop it.
Following are some scenarios of how the situation could unfold:
STREET PROTESTS TURN VIOLENT, PEOPLE GET BADLY HURT
The French government, and one of the main unions, appealed for protests to stay peaceful on Tuesday after skirmishes broke out in the city of Lyon and in a couple of Paris suburbs, with hooded youths torching cars and litter bins, smashing store windows with stolen cafe chairs and looting goods.
Police arrested dozens of people in Lyon and fired teargas to disperse protesters in the Paris suburb of Nanterre, where the mayor said some 200 youths set cars on fire and smashed public property. The suburb of Mantes-la-Jolie was hit by similar incidents, French media reported.
The French government is nervous of street rowdiness after mass student protests in 2006 that turned violent forced former President Jacques Chirac's government to ditch a labour reform introducing a new easy-hire/easy-fire contract for youths entering the job market.
In late 2005, rioting youths in Paris's tense and immigrant-heavy suburbs torched thousands of cars during weeks of clashes with police after two teenagers were accidentally electrocuted while apparently fleeing from police.
Any sign of people getting seriously hurt in disturbances around Tuesday's protests would require the government to send out police reinforcements and could force it to come out and make a concession on the pension bill.
PROTESTS FADE BUT STRIKERS DIG IN AND CRIPPLE TRANSPORT
A shortage of fuel has become the government's most pressing concern since workers at the country's 12 refineries walked out last Tuesday in sympathy with transport workers protesting the pension bill. Some fuel depots have also been blocked, although police intervened to clear access at a number of them.
The question is how far the government would be willing to tap into its emergency reserves in the days ahead, and how long striking refinery workers will be willing to keep losing pay.
The refinery strikes have come on top of an unrelated three-week strike at France's biggest oil port, Fos-Lavera near Marseille, which had already reduced crude supply at refineries in the southwest and depleted nearby fuel depots.
The UFIP oil industry lobby has warned that shortages will start to be felt from mid-week. On Monday, more than 500 petrol stations around France were suffering fuel shortages, and many drivers queuing for petrol or diesel said they had tried several stations in vain to fill up their cars.
French Energy Minister Jean-Louis Borloo said on Tuesday about one in three of the country's 12,500 service stations was suffering supply difficulties.
Prime Minister Francois Fillon said the government had put a plan in place that would secure a return to normal within four to five days.
As of Friday, France had 98 days of so-called strategic oil and fuel reserves, most of it held by the government but 30 days' worth held by industry and all of it stored in 120 depots across France. An International Energy Agency (IEA) official told Reuters France was already tapping the industry stocks.
UNIONS STEP BACK, RETURN TO TRANSPORT STRIKE
Unions may decide their negotiating position would be stronger if they scale back their action to strikes in the transport sector which disrupt daily life without the risk involved with police breaking up blockades or detaining protesters.
Rail workers continued their week-long open-ended strike on Tuesday and were set to do so on Wednesday, although the state rail company's forecasts of 2 in 3 high-speed trains running on Wednesday marked an improvement on 1 in 3 on Tuesday.
Tuesday's airport disruption was severe but mostly part of a one-day stoppage even if more limited disruption was expected on Wednesday because of calls by the CGT union at Air France for more protests at airports.
Union leaders will sit down on Thursday to decide what to do next and a Senate vote on the reform bill that was first due to happen on Wednesday may be delayed until later in the week because senators have to comb through hundreds of amendments proposed by opposition politicians in a move to hamper progress.
Tuesday's protests put as many people on France's streets as on a day of protest last week, which unions will take as a signal that support remains high.
But striking workers lose a day's pay for each day they are off work, and some say they cannot afford to stay away much longer.
Unions may also back down if they sense public opinion turning against them. Past polls have shown that most French people back the strikes but serious travel disruption could change that. So far it hasn't.
The big question there is the extent to which the national union confederations can control more radical union action at sectoral or regional level. (Editing by Charles Dick)