For context, I studied English as a foreign language as well as Japanese but I'm not fluent in Japanese, as well as international business and marketing. So in theory going to Japan for a year wouldn't seem out of place because of my university degree but I'll have a hard time finding a job related to all of that in my country so that's why I'm having doubts. Finding a job as a waiter seems easy from what I've been told, but less so as a language teacher and since English isn't my first language I'll look into teaching French even though there's less demand for that.
Ans sorry for the misunderstanding, I'm French but not Parisian. I answered that anon about Paris because I already visited the city before and I literally came back from a weekend in Paris a few days ago. I live in another big city which is also expensive but not nearly as much as Paris. I think prices like food and bills are similar though, but public transport and rents are definitely higher in big cities like Tokyo unless I choose to go to a sharehouse or a guesthouse (which is what I planned in the first place). I also think a lot of clothing brands are cheaper in Japan so I'll take advantage of that. Same thing for manga and restaurants.
I do plan on at least going to Tokyo, Osaka, Sapporo, Fukuoka and Okinawa because these cities seem interesting or I know people living there. I'll try to visit other cities next to these like Kyoto just like you said, Nara, Yokohama, Kobe, etc.
Why did you stay in Japan, work, internships, college, something else? Did you already speak and understand Japanese well before that trip, and how much did you improve? And did you stay in sharehouses or you managed to get your own places?