Food Tour in Paris

Most of the highly rated tours limit to 10 as do the tour guides on toursbylocals. If I were you I would contact as many of these as you can find about accommodating a group of 12 -- maybe one of them will bend the limit for you.

We did a cheese tasting with some wines at Parole des Fromagers and really enjoyed it. I think our group was about 10 but they might be able to squeeze in 12 -- worth inquiring. The aging room was tight -- 12 would have been a challenge, but the tasting table/cellar might handle 12.
https://parolesdefromagers.com/formations/art-associations-fromages-vins/
I'd just contact them or the others directly describing what you need and when you will be there and see what they can do.

Maybe one of them is game.

Eating Europe

This one has Max of 12 people
https://www.eatingeurope.com/paris/montmartre-food-tour-2-2/

as does this one
https://www.eatingeurope.com/paris/pariswinetour/

This has max of 11- but maybe they'll accept 12
https://www.eatingeurope.com/paris/juliachildparis/

We have not done any of these in Paris but have done others with Eating Europe and they have all been fantastic
use EATWELL10 for a discount

We have done a wonderful tour with Lisa Rankin and Flavors of Paris - St. Germaine and will do the Marais in a few months!
I don't know the limit, but she has been helpful and response to us over the years. Give her a try!
lisa@FlavorsofParis.com

Basically you need to contact the vendors and ask for a private tour for 12. They do those

I’d avoid Secret Food tours. Did one last week and was not impressed

Thank you, Carol for that info. They are (were !) on our list for this summer.

Paris by Mouth might be an option. They are highly regarded.