In my opinion Nathalie is helping Gabriel/Hawkmoth is because she loves him.In "style queen" the ending when Hawkmoth almost gives up, he comes and sits down in a chair stressed like, Nathalie seeing him walks over and put her arms around his neck and comforts him.then in another episode (i can't remember) she tells Doozoo that SHE herself wants to give ladybug and cat noir's miraculous to Hawkmoth. so why is she doing all of this? what does she get in return?(i am guessing nothing) the only explanation is she loves him. but Gabriel/Hawkmoth wants the miraculous to bring back Emily. So what Nathalie thinks won't happen.that's my opinion so give a comment, thanks for reading.