PARIS (AFP) - French public sector workers went on strike Tuesday, disrupting train services and schools in another challenge to President Nicolas Sarkozy after his partys stinging election defeat. Frances major unions called the national day of action to protest job cuts and plans for pension reform, a centrepiece of Sarkozys agenda for the second half of his mandate. The protests came a day after Sarkozy dismissed his labour minister and reshuffled his cabinet in response to a humiliating defeat by the left in regional elections. Paris area commuters faced some disruption with half of trains running on some suburban lines, while the state-owned SNCF rail authority said nearly two-thirds of high-speed TGV trains were up and running. One in five primary and high school teachers went on strike, the education ministry said around midday, as unions called for a strong turnout to protest the governments plan to replace only half of retiring staff. Frances biggest union, the CGT, said 180 protest marches were planned in cities and towns across the country. CGT leader Bernard Thibault called on Sarkozy to chart a new course for his economic policy to urgently tackle unemployment now at 10 percent and falling living standards. The issue is getting new direction in economic and social policies, said Thibault. Union leaders said they were not expecting a massive show of force but stressed the strikes would put labour issues back at the top of the political agenda. We must send a strong message to the government, said Francois Chereque, head of the CFDT union. French workers are increasingly feeling abandoned by Sarkozys govt, he said. The govt must change its methods. About 12 percent of postal workers were taking part in the strike, the postal services said, and strikes were also planned at France Telecom. Many union activists were mobilising over Sarkozys plan to raise the legal retirement age, possibly to 62. The government argues this is the only way to keep the system of generous benefits afloat. Talk of raising the retirement age has been taboo in France where the right to a pension from age 60 has been enshrined since 1982, a legacy of Socialist president Francois Mitterrands administration. On Monday, Sarkozy sacked Labour Minister Xavier Darcos who suffered a heavy defeat in the western region of Aquitaine, replacing him with Eric Woerth, who will now be the point man on pensions reform. Francois Baroin, who had served as a minister during Jacques Chiracs presidency, was appointed to replace Woerth as budget minister. His appointment was seen as a bid to appease the centre-right members of the party. Two other centre-right UMP members were named to junior posts: Georges Tron as minister responsible for the civil service and Marc-Philippe Daubresse as minister responsible for youth and anti-poverty measures. Sarkozy was elected in 2007 on promises to boost Frances economy and get people back to work, but last years recession has driven unemployment up to 10 percent, its highest level in a decade. Many observers saw Sundays electoral defeat for the government as a verdict both on Sarkozys policies and his style. The Socialist-led opposition beat Sarkozys Union for a Popular Movement (UMP) party by around 54 to 36 percent in the vote, leaving the left in control of 21 of Frances mainland regions.