If You compare to London for example , Paris is a little late in term of proposition for street food festival or street food market but it tends to improve more and more ( last summer saw 4 different new proposition so it's bubbling ...  

I m gonna try to give you some info about what's going on month by month . 

I m very sad to learn that the street food festival planned sept 23/24/25 had to be canceled for security reason . See u next years hopefully 

La Street Food Party is on every saturday nigh at the Délirium Café ( Paris 2 ) 

the story started in 2015 and is still running due to its constant success . 

every Saturday, hundreds of amateurs of street food find themselves to have a Junkfood extravaganza time with the best of the current street food, without having to run after food trucks in every corner of Paris, with menus imagined for the occasion; the Hummus Bar, Black Spoon, WokNRoll and many others else are there. Having tasted the various specialities of trucks make sure you excercise in the clubbing area till 5 am in the morning!

Where : Metro Belleville 

When : 2 thursday a month from 6:30 to 10pm 

the best open ai street food festival in Paris running for its 3rd year now 

this time The Food Market will team up with "Action Against Hunger" so a part of the proceeds will go directly to charity . and for htos eof you who can't make on thursday , those restaurant are doing the same int their own restaurants or food truck for the whole month