* March had been due Nov. 29, on eve of climate summit
* Organisers to meet Monday to review plans
By Bate Felix
PARIS, Nov 15 (Reuters) - A massive demonstration planned by environmental activists for the eve of this month's U.N. climate summit in Paris is in doubt as organisers weigh the security risks - and the propriety - of gathering in huge numbers in a city where attacks killed 129 people.
Environmental groups will meet on Monday to decide a course of action, with mainstream activists saying they will abide by any ban on public gatherings if the state of emergency decreed by French President Francois Hollande is still in place.
Organisers from about 130 non-governmental organisations had hoped to draw 200,000 people to the march on Nov. 29, anticipating a carnival-like atmosphere that would pressure world leaders to take action to combat global warming.
"We are horrified by the attacks," said Alix Mazounie of Climate Action Network in France, one of the groups planning the gathering to put pressure on world leaders attending the Nov. 30-Dec. 11 summit, convened to work out a plan to combat climate change.
The coalition organising the Global Climate March will meet on Monday at 1400 GMT to discuss how best to proceed. Among the risks is that security fears will keep the turnout - and the political impact - low.
"It is for the French presidency to decide on the way forward, and we will make changes to our plans as appropriate," said the aid charity Oxfam.
Under French law, a state of emergency can last 12 days and Prime Minister Manuel Valls has said it may be extended if needed. France says the summit itself will go ahead, and leaders including U.S. President Barack Obama have reaffirmed attendance.
If security and respect for the victims force cancellation of the Paris demonstration, one option is to boost other planned parallel demonstrations in cities such as Sydney, Tokyo, London or New Delhi on Nov. 29.
Organisers said they also hope to find some way of combining tributes for the victims of the Paris violence with their appeals for action to protect people from the impacts of climate change, such as floods, droughts or rising sea levels.
Activists could be encouraged to take to social media instead of to the streets.
The march had been due to start at the Place de la Republique, in the neighbourhood where some of Friday's attacks took place. Organisers had hoped the turnout would rival a peaceful march for action on climate action in New York last year that activists estimated drew 310,000 people. (With extra reporting By Nina Chestney in London and Alister Doyle in Oslo; writing by Alister Doyle; editing by Bruce Wallace and Digby Lidstone)
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