My husband is allergic to a wide variety of things (corn, soy, sesame, peanuts, cantaloupe, cod and clams). I lived in France for a year in college and took French in high school/college, so it helped that I had some residual communication skills (we've brought cards with pictures of his allergies to other countries in the past when English was less widely spoken or our local language skills were lacking). Part of traveling fun is being able to stop at any place that strikes your fancy, but with allergies we found it helpful to do some advance research of restaurants that have posted menus, and to make reservations (sometimes you can even make notes about the allergies in your reservation). Even if the restaurant's menu changes seasonally, you can at least get an idea of their type of cuisine. I'm not sure what your budget or other preferences might be, but Food and Wine has some fun food guides that list a few key dishes for each recommendation.
We went to Normandy and Paris in April 2018. In Paris, we found that Pomze, Chez l'Ami Jean and Breizh Café were good fits (understanding about allergies, some options with simple ingredient lists that make it easy to decipher, etc). A steak frites restaurant (like Relais de l'Entrecote) would also probably be a good choice. I'm sure you'll find that kindness and patience go a long way in getting people to help you, and that enthusiasm for their food overall lets them know that you're concerned about safety, not just being picky. Bon voyage!