My daughter is now 21, and her room went through multiple transitions........from nursery with white walls and wallpaper border to butterfly room (with multiple colors of paint & white picket fence) to now white walls with a navy & red nautical theme. As an older Mom and homeowner I can tell you that styles change and most can be accomplished with colorful accents and rugs and white or off white walls.

The photo you supplied shows a grayish tint paint which echoes the headboard and mirrored facade. If you want color I'd maybe put in colorful lampshades, pillows, comforter/bed spread, seating and rugs.

When I have redecorated I find everything I want by googling. I just googled "Paris removable wall stencils" and there are dozens on Amazon, and many other specialty stores, some quite colorful. I also googled "Parisian lamp shade" and there are tons of them, also colorful or plain.

Once you decide on the accent color(s) she wants, specify it in your google searches like "pink Paris (fill in the blank with item)" and you can find anything to mix & match.

Good luck!