Updated
No — Self Modern isn’t listed as a free font. Bretagne Type Foundry releases it, so licence options and pricing sit on their site.
Self Modern is a serif typeface from Bretagne Type Foundry.
The starting point of Self Modern were specimens of traditional serif Japanese typefaces, called "Mincho", found in magazines & books that I brought back from Japan in 2015. I added to these references my researches on automatic composition systems, the “Self Spacing Types” in particular. The typeface is also designed to work with Japanese characters at the same size and weight. The Book, Semi-Bold and Bold versions, drawn in collaboration with Roxane Gataud, were added in 2021.
A1 features 2 websites using Self Modern, including Sania Saleh and Spaces. They lean towards Typographic, Overlapping, and Varied layout design styles, and they’re most often built with Webflow.