  We study the quark structure of the sigma meson through the decay of
$D_1(2430)$ meson by constructing an effective Lagrangian for charmed mesons
interacting with light mesons based on the chiral symmetry and heavy quark
symmetry. Within the linear realization of the chiral symmetry, we include the
P-wave charmed mesons ($D_1(2430)$, $D_0(2400)$) as the chiral partners of
($D^\ast$, $D$), and the light scalar mesons as the chiral partner of the
pseudoscalar mesons. In the light meson sector, both the $q\bar{q}$ and
$qq\bar{q}\bar{q}$ states are incorporated respecting their different U(1)$_A$
transformation properties. We predict the $D_1 \to D\pi\pi$ decay width with
two pions in the $I=0,\,l=0$ channel, which can be tested in the future
experiment. We find that the width increases with the percentage of the
$q\bar{q}$ content in the sigma meson.
