PARIS (Reuters) - Demonstrators unfurled a banner declaring "Gas & nuclear are not green" outside France's foreign ministry on Tuesday in protest at a government drive to label nuclear energy and fossil gas as sectors for climate-friendly investment.

       One of the about 20 protesters, wearing a mask of President Emmanuel Macron, chained himself to a gas bottle and a nuclear barrel outside the ministry's headquarters in Paris. Another held a banner that read "Macron shame on you."

       The European Union is preparing a rulebook on climate friendly investments, which from next year will define which activities can be labelled as green in sectors including transport and buildings.

       The EU's aim is to restrict the green investment label to climate-friendly activities, steer cash into low-carbon projects and stop companies or investors making unsubstantiated environmental claims.

       The French government hopes that having the sustainable energy label could boost France's struggling nuclear energy industry, which was bailed out by the state in 2017 following construction delays and cost overruns.

       "By taking the lead of the toxic alliance between fossil gas and nuclear (energy) at a European level, Emmanuel Macron clearly sides with the polluters' camp. Nuclear is not a green energy: it produces radioactive waste that piles up across the country", said Nicolas Nace, a member of environmentalist group Greenpeace.

       Finance Minister Bruno Le Maire said last month that one of the priorities of France's six-month EU presidency, starting on Jan. 1, would be to include nuclear power in Europe's sustainable finance taxonomy.

       Some EU countries, including Germany, do not agree with this policy.

       France generates about three quarters of its electricity in nuclear reactors operated by state-owned utility EDF.

       (Reporting by Lea Guedj; Writing by Benoit Van Overstraeten; Editing by Geert De Clercq and Timothy Heritage)