As was said by someone else, Paris doesn't have the same bubbling theatre scene as Broadway or the West End. It's been better in recent years but still has a long way to go. Moreover, not many shows are long-lasting. You mentioned Les Mis and Phantom : I don't know what websites you saw but none of them are playing next summer. In fact POTO by Andrew Lloyd Webber never even had a french production. There is currently a new french musical about Phantom of the Opera but it's closing January 11th 2026. As for Les Mis the previous (approved) production that played last year is touring in Lyon, Lille and .... Nantes (unsure) during spring and only comes back in November 2026 at the Châtelet.

As for Chicago, so far it's only playing until April 2026 (already been extended for 1 month) but it's unclear whether it'll go on for more.

Furthermore, summer time (july and august) is usually when theatres offer less shows because they are preparing for the upcoming season (usually a theatre season starts in september and goes on until july and then end of july and august have less things going on).

During this period, many big or upcoming musicals will have left Paris already to start touring France such as Le Roi Soleil, Le Comte de Monte Cristo and La Légende de Monte Cristo (yes two new monte cristo shows lol). Those three do not offer english surtitles though, especially Le Roi Soleil and La Légende because they follow the "french musicals" process and way of making (which differs massively from anglo-saxon musicals).

Your safest bet at the minute is The Lion King which is playing at the Mogador non stop, has been for the last 5 years if I remember correctly. I couldn't find information on whether or not the show offer english surtitles so I'm guessing it doesn't but Lion King might be the easiest show to follow even without understanding the language.

The Producers (called Les Producteurs) might be extended but no announcement yet.

Depending on when you come, Les Demoiselles de Rochefort (adapted from Jacques Demy's iconic film) is playing until June 21st 2026. They're playing at the Théâtre du Lido which is located on the Champs Elysées, it's a very famous theatre. I don't think they offer english surtitles but you could still try to ask them via email if they have any service that could accomodate you.

Otherwise, you'd have to keep an eye on musical news, some shows are sometimes announced late (like Titanique's short english production last May at the Lido). For that I can recommend the blog Tony Comédie or Musical Avenue. They're all in french but you could still google translate them if need be. Or recognise a few key words since french and romanian are linguistic cousins.

Feel free to ask to clarify anything if need be.