  Let $F$ be a totally real number field of class number one, and let $K$ be a
CM-field with $F$ as its maximal real subfield. For each positive integer $N$,
we construct a class group of certain binary quadratic forms over $F$ which is
isomorphic to the ray class group of $K$ modulo $N$. Assuming further that the
narrow class number of $F$ is one, we construct a class field of the reflex
field of $K$ in terms of the singular values of Hilbert modular functions.
