Ciel Blue Marché (シエルブルーマルシェ) is a cheerful, French-inflected original song created for maimai でらっくす PLUS, the first expansion of the maimai DX era. The track was produced by OSTER project, a female composer and producer affiliated with beatnation RHYZE, known primarily for her VOCALOID works and contributions to the BEMANI series, marking her debut original commission for the maimai franchise. Vocals are provided by Kanata.N (かなたん), a singer whose credits center on BEMANI rhythm-game songs, making this her first appearance in a maimai title as well. The jacket artwork and music video were handled by the circle Gunjou Licorice (群青リコリス). With a brisk BPM of 180 and lyrics about a sunny morning market expedition, the song radiates a light, upbeat energy that matches its name, a fusion of French ciel bleu (blue sky) and marché (market). Among the five DX charts, the Re:MASTER difficulty (level 13+, constant 13.7) stands out for its extreme Slide-note emphasis: 216 Slide notes against only 1 Hold and 1 Touch, a signature design by charter はっぴー that prioritizes sweeping, flowing patterns over the usual hold-and-tap density.