A metre gauge railroad has its rails (obviously) one metre apart. Metre gauge was the most common large narrow gauge standard found in European-promoted narrow gauge systems, whereas 3' gauge was most commonly found in American-promoted systems. Perhaps because the smaller British loading gauge made Standard Gauge British rolling stock little larger than such large narrow gauge systems elsewhere, British-promoted narrow gauge systems tended to be 2'6" gauge and smaller.
Most narrow gauge railroads in Switzerland, Austria and France were metre gauge, as were many systems built in their colonies.