A military coup in the CAR a few months ago has led the country down a violent path, leading to the UN approving French and African military forces deployment.
"It is clear that urgent action is needed to save lives," said US Ambassador to the UN Samantha Power.
At least 105 people have been killed in the capital in clashes over the past few months. French and African forces have been sent to protect civilians and hopefully prevent the outbreak of a nasty sectarian war.
"I'm worried what kind of reprisals there will be later. Nobody is moving and it's a real ghost town," said Sylvain Groulx of Médecins Sans Frontières.
The conflict is between former rebels called the Seleka and Christian vigilante groups known as the "anti-balaka".
After the UN approved France's involvement, French President Francois Hollande released the following statement: "Given the urgency, I have decided to act immediately, that is to say as of this evening in coordination with the Africans and with the support of European partners. Already 600 French troops are there. This number will be doubled within a few days, if not a few hours."
Hollande has been criticized at home for getting involved in foreign military conflicts including in Mali and his support for US intervention in Syria.