Supermarket chain Aldi was facing controversy after demanding employees working near the site of the hostage standoff between police and the Charlie Hebdo shooters have to make up for the time lost during the incident.

Friday 9 January was not a usual working day for warehouse staff of the discount giant in Dammartin-en-Goële, 40km north east of Paris.

Their workplace was metres away from the printing plant where Islamist gunmen Cherif and Said Kouachi had holed up with a hostage.

Some workers were unable to get to work in the morning as police had cordoned off the entire industrial area.

Those who had arrived at the premises were locked inside until officers ordered them to evacuate in the afternoon, as special units prepared to launch an assault on the jihadi brothers.

Approximately 15 Aldi employees had their seven-hour working day disrupted by the events of the last of France's three days of terror unfolding round the corner.

The Kouachi brothers were eventually shot dead by police and, as life returned to normal, the discount chain management told its workers they had to make up for the time lost that day.

"I'm outraged," trade union representative Laurence Moissard told Le Parisien, explaining that the staff had to leave work for security reasons.

"We should have told the GIGN [France's Counter Terrorism unit]: 'Wait, we can't leave now, we have not finished our seven hours!'"

Aldi confirmed the measure but specified no salary reduction will be made.

Local Aldi manager Bertrand Combot told the newspaper some employees would actually benefit from the situation.

He said those who remained stuck at work for more than seven hours, due to the police lockdown, will have the extra time credited for.