Ottilie has a slight coolness to it, so the whole job is about warming that up rather than fighting it. The mistake people make is pairing it with brilliant white woodwork — that turns Ottilie grey and lifeless. Go warm instead.
For adjacent woodwork and ceilings, Farrow & Ball Au Lait (LRV 80) is your safest bet — a creamy, milky off-white that lets Ottilie breathe without going stark. Paper III from Paint & Paper Library (LRV 75.3) does the same job a touch cooler if you want a little more crispness while staying off the harsh end. Either of these on the trim will keep the whole scheme soft and considered.
For depth and contrast, layer in clay-pinks and warm earth tones. Mylands Cigar BH.20 (LRV 11.8) is a gorgeous deep grounding shade — think tobacco-brown, lovely on a lower wall, a study, or cabinetry where you want Ottilie to feel anchored rather than floaty. And if you fancy a bolder accent, Dulux Fuchsia Falls 2 (LRV 29.8) pulls out the warmer rosy undertone and gives the scheme a bit of life — good for a single piece of joinery or a feature wall rather than the whole room.
The other thing that genuinely matters here: metals. Antique brass and aged bronze warm Ottilie and make it sing. Chrome, nickel and anything silvery does the opposite — it pushes the colour towards grey. So pick brass handles, bronze taps, aged hardware. Same goes for old oak — Ottilie loves natural timber tones beside it.
Practically: paint a decent-sized sample board, prop it against your intended white, and check it morning and evening. Ottilie's coolness shows itself more in north light, so if you're in a cooler room lean harder into the warm off-whites and the brass to balance it out. Get those two things right and it's a cracking colour.