I saw a post on Tumblr by cleenglish talking about how English proofreading was requested. I don't speak French, sorry. ;~; Otherwise I would've written in French, but alas, I only know a few words from trips to Montreal. I tried to write down any reasons too, since it really helps me in Spanish (which I'm studying in school) to know the reason behind a grammar rule or a correction. This translation is really good, and it's a lot better than what I can do from English to Spanish! It's also very accurate, so most of my corrections are just me nitpicking and being annoying about it.
Spoiler
Citation:
Many mysteries float over the birth of the monsters and the secret of their making seems to be well-kept by XANA. The existence of a monsters factory is surely impossible…
"Many mysteries surround the birth of the monsters and the secret of their making seems to be well-kept by XANA." I would use "surround" instead of "float over" here. "Mysteries surrounding..." is a common phrase in English.
Citation:
They could be made by a basic program, containing all their characteristics, which would allow XANA to create really similar monsters, as like as two peas in a pod… It would match with the program created by Jeremy to virtualize vehicles. Something sure: the monsters are not virtualized after a dematerialization and are not based on a body which already exists…
"They might be made by a basic program, containing all their characteristics, which would allow XANA to create really similar monsters, like two peas in a pod." "As" also isn't needed in this phrasing.
"...and are not based on bodies that already exist." (I hope I didn't understand this wrongly, but by "body" I understood this to mean "a creature/monster existing in real life and not on Lyoko")
I would use "bodies" here instead of "body" because we're talking about monsters, so it makes sense to pluralise "body" too. The "which" and "that" rule is really tricky since the difference between them is very subtle, and it took me a long time to understand it. I would use "that" here, but honestly, this is me being really annoying. No one would care whether "which" or "that" was used here.
Citation:
We have seen that, in some episodes, like the 36 (Marabounta), XANA virtualizes its creatures right in the field like Jeremy does with his virtual fighters.
"We have seen that, in some episodes, such as..." "Such as" is used to suggest a possibility, and you would use it in the same manner as "for example." The word "like" is used to (sometimes very subtly) suggest a comparison.
I would either use "such as the 36th episode" or "such as episode 36."
Citation:
The Mantas give us an other element for the answer : when the heroes start te sneak into Carthage's interface, Jermy talks about a "hatching". We can now see the sublime blue creatures rooting out the digital sky which englobs the Sector 5. They seem to appear suddenly from the inside of digital datas. If they are created by a program, well, they are not virtualized (or from the inside of the digital sky, without being seen)… In the episode 55 "Tidal Wave", it's a Creeper which roots out. After its birth, it is launched upon the platform and lands, ready to fight !
"The Mantas give us another element..." Another is one word.
"When the heroes start to sneak into Carthage's interface, Jeremy..." These were just a couple of spelling mistakes.
"...which englobes Sector 5." I think an "e" was just forgotten in englobes! And Sector 5 doesn't need an article, so the word "the" isn't needed before it.
"In episode 55..." The "the" isn't needed here.
"a Creeper that roots out." It's hard to explain the "that" and "which" difference (I think it's kind of like "À" and "De" in French...for English speakers, their differences are really difficult to understand), but I would use "that" here.
The phrase "roots out" makes me think of seeking something out, looking for something, or trying to eliminate or get rid of something. "A Creeper that comes out" might sound better!