  We present a new method for accurate mid-infrared frequency measurements and
stabilization to a near-infrared ultra-stable frequency reference, transmitted
with a long-distance fibre link and continuously monitored against
state-of-the-art atomic fountain clocks. As a first application, we measure the
frequency of an OsO4 rovibrational molecular line around 10 $\mu$m with a
state-of-the-art uncertainty of 8x10-13. We also demonstrate the frequency
stabilization of a mid-infrared laser with fractional stability better than
4x10-14 at 1 s averaging time and a line-width below 17 Hz. This new
stabilization scheme gives us the ability to transfer frequency stability in
the range of 10-15 or even better, currently accessible in the near-infrared or
in the visible, to mid-infrared lasers in a wide frequency range.
