Police impounded the French stick as evidence and gave the 15-year-old a caution.
The baguette was one of 80 weapons seized by police in East Sussex over the past two years, details of which emerged after a Freedom of Information request.
Some were obviously dangerous, such as knives and a gun, but others confiscated by officers included rulers and pencils.
The Argus in Brighton reported one incident that involved a 13-year-old "armed with a piano stool and a xylophone".
Another attack was carried out with an egg and a tomato, while one 13-year-old received a warning after assaulting another pupil with a pillow.
Trevor Allen, headteacher of Dorothy Stringer School in Brighton, did not recall any problems with weapons at his school.
"There certainly haven't been any with baguettes," he told The Argus. "They'd have to be three days old before they'd be any use as a weapon anyway."