As was noted on the page on units used in printing, just as the point used for printing in the English-speaking countries began as 1/72nd of an inch (but was then adjusted to 0.013837 inches), the Didot point was 1/72nd of the French inch, twelve of which made up a French foot, also known as the Pied du Roi.
Prior to the adoption of the metric system, the basic unit of length used in most of the countries of Europe was a foot of one sort or another, and the basic unit of weight was a pound of one sort or another, these units being inherited from the Roman empire. But in each country, the standards for these units had changed over time, and, so, as the modern era arrived, and it was possible to standardize the units to a higher level of accuracy than achievable in the ancient world, serious differences existed between the units of one country and another.
Some units, such as the mile and the ell, were defined differently in terms of other units in different countries as well.
One old book gave the lengths of the feet used in several different countries and cities as follows:
inches ------- Spain 11.128 Amsterdam 11.147 Hamburg 11.289 Munich 11.37 Ancient Rome 11.60 Rome 11.72 Sweden 11.684 Rhineland 12.35 Prussia 12.356 Denmark 12.356 France 12.7893 Portugal 12.944 Austria 13.68 Russia 13.75
and, similarly, it gave the weight of the pounds used in different places as:
pounds ------- France 1.08 Spain 1.0144 Portugal 1.0119 Russia .9026 Prussia 1.0311 Hamburg 1.068 Sweden .9376 Denmark 1.103 Belgium 1.0893 Rome .7477 Livorno .75 Genoa .76875 Sicily .7 Naples .7067 Trieste 1.236 Malta 1.75