  We present the first X-ray observation at sub-arcsecond resolution of the
high-redshift ($z=6.18$) radio-loud quasar CFHQS J142952+544717 (J1429). The
~100 net-count 0.3-7 keV spectrum obtained from $\sim 30$ ksec Chandra exposure
is best fit by a single power-law model with a photon index $\Gamma=2.0\pm0.2$
and no indication of an intrinsic absorber, implying a 3.6-72 keV rest-frame
luminosity $L_{\rm X}=(2.3^{+0.6}_{-0.5})\times10^{46}$ erg s$^{-1}$. We
identify a second X-ray source at 30 arcsec, distance from J1429 position, with
a soft ($\Gamma\simeq 2.8$) and absorbed (equivalent hydrogen column density
$N_{\rm H} <13.4\times 10^{20}$ cm$^{-2}$) spectrum, which likely contaminated
J1429 spectra obtained in lower angular resolution observations. Based on the
analysis of the Chandra image, the bulk of the X-ray luminosity is produced
within the central $\sim 3$ kpc region, either by the disk/corona system, or by
a moderately aligned jet. In this context, we discuss the source properties in
comparison with samples of low- and high-redshift quasars. We find indication
of a possible excess of counts over the expectations for a point-like source in
a 0.5 arcsec-1.5 arcsec ($\sim 3-8$ kpc) annular region. The corresponding
X-ray luminosity at J1429 redshift is $4\times 10^{45}$ erg s$^{-1}$. If
confirmed, this emission could be related to either a large-scale X-ray jet, or
a separate X-ray source.
