Papa-tachi no yō na Furansugo o kajitta Nihonjin-tachi ga tsukuridashita shinzōgo ni tatamizei to iu no ga aru ga, sore wa tatami ka shita to iu imi de, itsu no aida ni ka, tsukemono-kusaku gaijin ga naru koto de, Mama wa masani tatamize shite-kita no dearu.
Japanese people like Papa who speak a little French made a neologism, tatamiser, but that means “became tatami mats”, and before you know it one becomes a pickle-smelling foreigner, as Mama certainly on s’est tatamisé.
2015, Tristan Brunet, Suiyōbi no anime ga machidōshii: Furansujin kara mita Nihon sabukaruchā no miryoku o tokiakasu [Longing for Wednesday’s anime: Explaining a French person’s fascination with Japanese subcultures], →ISBN, page 30:
Furansu-go ni wa “tatamize” (tatamiser) to iu kotoba ga aru no desu ga, go-zonchi deshō ka? Mochiron kore wa “tatami” ni yurai suru kotoba de, chokuyaku sureba “tatami ka” to itta kanji. Moto wa Nihon fū no kurashi o shitari interia o konondari suru hito o sasu hyōgen deshita ga, genzai de wa hiroku “Nihon bunka ni somaru hito” zentai ni taishite tsukaemasu.
There is a French word, tatamiser, but I wonder if you know it? Of course it comes from the word tatami, and a direct translation would be something like “become a tatami mat”. Originally it was an expression used for a person with an affinity for Japanese-style interior design, but these days it is most often used to mean “a person steeped in Japanese culture”.