Security concerns dominate Paris on eve of COP21

France’s capital is on high alert as it prepares for the arrival of 147 heads of states for the Monday opening of the COP21 United Nations Conference on Climate Change.

“We are not used to such a police presence,” said one Parisian on Sunday.

Everywhere, from under the Eiffel Tower to the Arc de Triumphe, machine-gun toting policemen and soldiers stand on guard by Paris’ best known landmarks. Many people are being detained and questioned after the Nov. 13 ISIS attacks on the city.

Siren-blaring army vehicles stream past main thoroughfares and officials cancelled a massive climate march downtown Paris due to security concerns, forcing climate protesters to be inventive.

Activists created a "human chain" in a one scaled-down rally downtown. At another location, thousands of shoes were placed to symbolize those prevented from protesting.

"I think I want to salute the creativeness of Parisians finding all sorts of ways to show their support for a positive conclusion of negotiations, despite the fact that they can't walk," said Steven Guilbeault, co-founder of Equiterre, in Paris on Sunday.

One of the main highways leading to the COP21 / CMP11 mega-summit site will be closed to one lane, to make way for the stream of world leaders.

Paris’ subways are free of charge today and Monday to limit traffic chaos.

Prime Minister Trudeau arrived Saturday and is expected to present Monday at the UN conference along with U.S. President Obama.

Foreign Affairs Minister Stephané Dion and Environment and Climate Change Minister Catherine Mckenna will speaking to press shortly.

Updates to come.