Consider $n geq 2$. In this paper we prove that the group $text{PU}(n,1)$ is $1$-taut. This result concludes the study of $1$-tautness of rank-one Lie groups of non-compact type. Additionally the tautness property implies a classification of finitely generated groups which are $text{L}^1$-measure equivalent to lattices of $text{PU}(n,1)$. More precisely, we show that $text{L}^1$-measure equivalent groups must be extensions of lattices of $text{PU}(n,1)$ by a finite group.
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