With her father, ex-Beatle Paul McCartney, in the audience, the British designer held her Paris Fashion Week show on Monday in the Palais Garnier, the ornate home of the Paris National Opera.
The show started with outfits in a natural palette, followed later by designs with touches of bright colour and bold graphic stripes. Over 75% of the ready-to-wear collection is eco-friendly, according to the label, using recycled polyester, organic cotton and sustainable raffia.
The Spring and Summer 2020 collection is McCartney's first one since LVMH took a minority stake in her eponymous brand.
The deal came a few months after the designer bought back a 50% stake from Kering, ending a 17-year partnership with the French conglomerate.
"There is a lot to be done at LVMH in a positive way and I am very excited and open to find some solutions (to sustainability issues)", McCartney told Reuters after the show.
"If I say to LVMH to stop using leather, they may find that pretty difficult," McCartney said.
"But if I suggest banning plastic water ... (bottles) in headquarters and stores and replace them with aluminium cans, that is doable. I can not only give advice but also plug in a solution pretty quickly. The list is very long and we have to start somewhere".
LVMH, absent from an industry "fashion pact" launched under Kering's auspices, said it was on course to beat a goal of meeting 30% of its energy needs from renewable sources by 2020 and also on track to cut its CO2 emissions by 25% by the same time.
Nevertheless, Arnault said last week that environmental activist Greta Thunberg's statements on climate change were overly pessimistic and demoralising for young people.