Green Party Mayor Grégory Doucet says adopting a single meatless menu helps to make social distancing easier during COVID-19.
Of the 30 million low-income students who are eligible for free lunches, only 15% are currently getting those meals.
The shutdown has school districts worried about their ability to feed students.
Schools in Texas are trying a new approach by offering free meals to all students.
About half of public school children today qualify for free and reduced-price meals at school. A new federal option allows high-poverty schools to feed all students at no charge.
Roughly half of public school children today qualify for free or reduced-price lunch, and that number drives billions of dollars in other benefits for schools. But critics say the program is prone to error and fraud.