The Mexican government has accused designer Carolina Herrera of cultural appropriation in her latest range.
The designer's website says the Resort 2020 collection "takes on the playful and colourful mood of a Latin holiday".
But Mexico's culture secretary has written to the fashion house complaining about the use of patterns from indigenous communities.
A spokesman for Ms Herrera, who was born in Venezuela, said the brand recognises Mexican artisans' work.
The spokesman added this particular collection was inspired "by the culture's rich colours and artisanal techniques", according to AP news agency.
What does the letter say?
In an unusual step, Mexico's culture secretary Alejandra Frausto sent a letter of complaint to both Ms Herrera, who gave up creative direction of the fashion house last year, and its new creative director Wes Gordon.
According to Spanish language newspaper El Pais, Ms Frausto told the designers that some of the patterns used in the collection are unique to certain regions of Mexico and their indigenous peoples, and asked whether these communities would benefit in any way from the sale of the clothes.
She then described the significance of some of the patterns, and asked the designers for a public explanation for how they came to use them.
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@carolinaherrera resort 2020 por @wesgordon Wes Gordon, quien lleva un año frente a Carolina Herrera, destaca en la generación de diseñadores jóvenes inyectando energía y trayendo al presente el ADN de casas neoyorquinas. Para la colección resort de Herrera, Gordon cita Oaxaca como una de sus fuentes de inspiración, de la propuesta destaca un vestido en jersey con estampado de sarape. Los looks propuestos por #WesGordon presentan la versión #CarolinaHerrera de distintos elementos de varios trajes típicos mexicanos que se fusionan con la pregunta que el diseñador se ha estado haciendo desde que fue nombrado Director Creativo de la casa de moda: ¿Cómo se viste una dama en el tiempo contemporáneo y la era del hype? Gordon contesta incorporando Herrera-ismos como las mangas abullonadas, vestidos voluminosos pero prácticos y retransformando la camisa blanca (ícono de la casa Herrera) para crear piezas auténticas a la esencia de la casa y que se leen como frescas. A lo largo de la colección Gordon también jugó con la sastrería, creando piezas sólidas pero con una sensibilidad inherente, sastrería para mujeres, no sastrería que aspira a decirle a las mujeres ‘MAN UP!’ Gordon nos dice que la dama actual no solo es una socialité que atiende galas y con esto, trae a Herrera al presente.
Ms Frausto gives the example of one long white dress with animal and floral prints on it, and says that its embroidery comes from the community of Tenango de Doria in Hidalgo.
She also took issue with two black dresses embroidered with bright flowers, which is typical of artisans from the Isthmus of Tehuantepec, and another dress that is based on a sarape - a shawl or blanket - from Saltillo.
"In these embroideries is the history of the community itself, and each element has a personal, family and community meaning," Ms Frausto said.
This intervention also comes just weeks after the Mexican government announced plans to allow indigenous groups to own the rights to their creations and "cultural elements", to prevent "plagiarism of their traditional designs".
How have others reacted?
The Resort 2020 collection had already been attracting a lot of criticism, both in Mexico and among Mexicans abroad.
One Twitter user noted that, as well as using embroidery "taken directly from hard-working artisans in Mexico", none of the models in the campaign were Latina.
Another wrote that when a number of designers refused to dress US President Donald Trump's family, in protest against his comments about Mexicans during his presidential campaign, Ms Herrera had said it would be "an honour" to dress First Lady Melania Trump.
"Love for Mexico: Only when it's lucrative?" the Twitter user added.
The designer's own tweet about the collection was also immediately flooded with replies accusing her of plagiarism, and the hashtag #MexicoSinPlagios - "Mexico without plagiarism" - began to trend.
But despite all of this, the collection still has its fair share of fans - including Mexican actor and singer Roger Gonzalez, who said the collection was "beautiful", and that it "puts Mexico in the sights of the whole world".