The Federal Government estimates that about 0.4% of Californians were homeless in 2020. From what I've seen on the streets the numbers are probably a little worse now.
By comparison, France has 300 000 homeless persons [1], which is about 0.44%. It doesn't seem to be as big an issue here compared to California. Maybe homeless people are more concentrated in SF which makes the problem appear worse than in other countries?
[1] https://www.lemonde.fr/societe/article/2020/11/15/la-fondati...