The French "Je t'aime" seems to be one of those popular expressions that used to find itself in a handful of Japanese pop songs and even some of the titles way back when. It is rather ironic that for a people who don't (didn't?) express affection too openly, the ardent l'amour did make its way into kayo lyrics.
One example that is well known to me since I'm a big fan of the singer is "je t'aime" by Ruiko Kurahashi（倉橋ルイ子）. Released as her 7th single in October 1984, the song may have all of its title in small letters but the way song comes out, it really seems to pour out all of the desperation of love and heartbreak like an avalanche. Going through the lyrics, I saw a lot of the tropes for the unhappiness involved in romance such as the dried and crumply leaves of autumn, the mark on the finger where a ring used to be, fog and even that new woman on the old flame's arm.
"je t'aime" isn't one of my favourite Ruiko songs partially due to the arrangement with a strangely dated synthesizer and because I usually like Kurahashi in a more languid style. But the song still pops up in my brain occasionally when her name comes up. It was written and composed by singer-songwriter Kuniko Fukushima（福島邦子）.