Mourners stopped in ones and twos by the building on the Rue Nicolas-Appert, where a plaque was unveiled on Tuesday.
Seventeen people died in January last year when gunmen targeted the magazine and a Jewish supermarket.
No official events are planned for Thursday, although President Francois Hollande is due to address the police.
Marine Le Pen, the leader of France's far-right opposition party Front National, is also expected to speak at some point during the day.
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As well as the memorial at the magazine's former office, a second plaque was installed where a police officer was shot, and a third at the Jewish supermarket.
On Saturday, a fourth plaque will be unveiled in the southern suburb of Montrouge, where one of the gunmen shot a policewoman.
The commemorations will culminate in a public event on Sunday in the Place de la Republique, where Parisians gathered in the wake of the attacks.
A 35ft (10m) oak "remembrance tree" will be planted in the square and veteran French musician Johnny Hallyday will perform Un Dimanche de Janvier (One January Sunday), a song recalling the vast march in Paris that followed the attacks.
Amid the commemorations, Charlie Hebdo has once again courted controversy with the cover of its special anniversary edition. It depicts God, bloodied and carrying a gun under the headline "One year on: The assassin still at large".

Pearce, 26, was also fined Aus $125,000 (£65,000), of which Aus $50,000 (£26,000) was suspended for two years.
He admitted he had a "problem with alcohol" and entered rehab after the footage emerged in January.
"Now this has been decided, I can get on with my rehab and work each day on making the right choices," he said.
The sanction, which will mean Pearce can return against the Newcastle Knights in the last week of April, was agreed upon by the Roosters and the NRL.
"This was a complex and unprecedented matter that required careful consideration," Roosters chief executive John Lee said.
"It was paramount we delivered the appropriate level of discipline, but neither could we ignore the player welfare component."
Pearce, the son of rugby league legend and NRL commissioner Wayne Pearce, was stripped of the Roosters captaincy after the incident.

President Salva Kiir's spokesman told the BBC Mr Machar "has no space here", and should not return to the country before elections in 2018.
Mr Machar, who had become vice president as part of a peace deal, fled the country following heavy fighting in the capital Juba in July.
But on Monday he vowed to return.
Speaking to the BBC from South Africa, Mr Machar said his rebel faction could still negotiate a peace deal with President Kiir.
In July, Mr Machar's bodyguards and President Salva Kiir's presidential guards fought each other, sparking days of violence.
Hundreds of people died and more than 100,000 fled across the border.
The fighting erupted less than a year after a peace deal was signed to form a unity government and end the civil war.
Riek Machar profiled
On Tuesday, President Kiir's spokesman Ateny Wek Ateny told the BBC that Mr Machar "will look for his space as a citizen of South Sudan, but not as a political leader".
Referring to the elections planned for 2018, Mr Wek said: "I don't think that he (Riek Machar) can even think to come (back) before that."
"It is better that Riek Machar stays away from South Sudan political scenes," the spokesman added.
Both President Kiir's and Riek Machar's followers have been accused of perpetrating atrocities during the country's bitter civil conflict.
More than 2.5 million people in South Sudan have been displaced since December 2013.
More on South Sudan's crisis:
Parisians have laid flowers and lit candles at the former office of Charlie Hebdo ahead of the anniversary on Thursday of the attack on the magazine.
[NEXT_CONCEPT]
Sydney Roosters have suspended scrum-half Mitchell Pearce for eight National Rugby League games after he was filmed committing a lewd act with a dog.
[NEXT_CONCEPT]
South Sudan's sacked Vice-President Riek Machar no longer has a role to play as a political leader in the country, the presidency says.