The dramatic ambience and fashionista crowd at Mantra almost overshadows the stunning French-Indian fusion cuisine served up my chef Thomas John but his classic culinary instincts and clever use of spices ultimately prevails at this fine-dining must where Boston’s Downtown Crossing and Theatre District intersect. The décor is breathtaking. This former bank from the 1800s has been transformed into an avant-garde masterpiece with its Italian marble walls and floors, halogen lights and saffron-colored silk drapery that makes seem like an experiential journey of the senses. Chain mail curtains and stepped tables evoke multiple rooms in the Beaux-Arts marble hall of the Old Colony Bank. Tip: Gentlemen, the urinals are disguised as ice machines. Ladies, your privacy is secure: the glass is one-way.