The trial of 14 suspects accused of involvement in the 2015 attacks on the satirical magazine Charlie Hebdo and the kosher supermarket Hyper Cacher has opened in Paris.

The hearing, expected to last 49 days and recorded live for “the historical record”, began amid high security and will relive the three days of terror in January 2015 that left 17 people dead and others injured.

It will hear from 144 witnesses, 14 expert witnesses and 200 interested parties, mainly the friends and family of the victims.

The attacks began on 7 January, when the brothers Saïd and Chérif Kouachi rampaged through the offices of the satirical newspaper Charlie Hebdo in the French capital, killing nine journalists and cartoonists, a building maintenance worker and two police officers.

On 8 January, Amédy Coulibaly gunned down a police officer in Paris; 24 hours later, Coulibaly, who pledged allegiance to Islamic State, stormed the Hyper Cacher supermarket in Paris, killing four Jewish people and taking others hostage.

All three gunmen were killed in shootouts with the police.

Afterwards, millions of people took to the streets under the banner #JeSuisCharlie in a show of solidarity with the slain cartoonists. The newspaper had infuriated Muslims worldwide by printing controversial cartoons of the prophet Muhammad.

Three of the suspects are being tried in absentia: brothers Mohamed and Mehdi Belhoucine and Hayat Boumedienne, Coulibaly’s girlfriend, who left for Islamic State-controlled areas in Syria or Iraq in the days before the attacks.

Hours before the trial opened, Emmanuel Macron, on an official visit to Lebanon, defended the “freedom to blaspheme” in France.

The president said: “Since the start of the Third Republic in France there has been the freedom to blaspheme, which is linked to the freedom of conscience … I am here to protect all these freedoms.

“A president of the republic is not here to qualify the editorial choice of a journalist or an editor because we have the freedom of the press, that we rightly hold dear … I will just say that in France one can criticise governments, president, blaspheme etc,” Macron said at a press conference.

He said he had a thought for the “men and women who were killed so cowardly” in the 2015 attacks.