After emergency services were notified of the incident in La Forge at 07:30 local time (05:30 BST) on Wednesday, around 80 firefighters were dispatched to the scene.
A property operated by a nonprofit organization that assists young people with disabilities looks to be where the fire began.
After 17 people were evacuated, at least one person was brought to the hospital.
Interior Minister Gérald Darmanin, who confirmed that a rescue effort is ongoing, said it was likely that a number of people were injured as a result of the fire in the town, which is located close to Wintzenheim and the German border.
The Haut-Rhin local administration issued a statement claiming that the 11 missing people were a group from Nancy, located in eastern France.
76 firefighters and four fire engines were dispatched to battle the incident, and despite the fire’s intensity, they were able to rapidly put it out.
According to Christophe Marot, no one has been found who was inside the structure when the fire started.
The families minister Aurore Bergé and French Prime Minister Élisabeth Borne are traveling to Wintzenheim to show their support for the victims and their relatives.
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