The operation targeted Abdelhamid Abaaoud, the suspected mastermind of Friday's terror attacks in Paris. Abaaoud was previously thought to be in Syria after fleeing raids in Belgium earlier this year.
The raids which took place in Saint-Denis before dawn, turned into an hours-long stand-off between security forces and up to four people holed up in an apartment.
A source close to the investigation said a woman in the apartment had blown herself up and one other person was killed, while police said five people had been arrested including a woman.
Dozens of soldiers had flooded into the area and heavily armed police were seen deploying along a street full of shops in the centre of the district, while ambulances and fire engines filled the streets.
Some residents were evacuated and authorities warned residents to keep away from windows.
A French police dog named Diesel was killed during the operation. According to the twitter account of France's police, a seven-year-old Belgian Shepherd, female assault dog named Diesel was killed by terrorists during the operation.
The hashtag #JeSuisChien (I am a dog) was trending on French Twitter after the announcement.
Schools and universities in Saint Denis have been closed while public transport was disrupted in the area because of the anti-terrorist operation.
Police also carried out multiple raids in south western France, in Ariege, Toulouse and the department of the Haute-Garonne.
Meanwhile, French President Francois Hollande will hold discussions today on extending the state of emergency to three months following the worst terror attacks in French history.
He will also meet US President Barack Obama in Washington on November 24 and Russian President Vladimir Putin on November 26.
President Hollande urges nation not to give in to fear
The French President urged the nation today not to "give in to fear" or excessive reactions in the wake of the jihadist attacks on Paris.
“No anti-Semitic or anti-Muslim act can be tolerated,” he told a meeting of the nation's mayors after police carried out a massive assault in Paris targeting the alleged mastermind of the assaults.