Michelin is right and other tyre manufacturers typically state the same. Continental goes a little further into it by saying –
“However, if mixing becomes unavoidable due to a lack of availability or budget constraints, then it’s possible to mix tyre brands and tread patterns – but only so long as drivers fit a “pair” of tyres with the same tread”
https://www.continental-tyres.co.uk/b2c/tyre-knowledge/mixing-tyres/