English term (edited): burden resistor load

The secondary load of a current transformer is called the "burden" to distinguish it from the primary load. It is a low-value resistance across which a voltage is generated, which is proportional to the current in the transformer primary, and which can easily be monitored using a simple voltmeter calibrated in transformer primary circuit ampères.

The preferred French term for this 'burden' is fardeau (or fardeau sécondaire) - which avoids confusion with charge which is used for many other concepts in this context (and in Asker's text would create nonsense such as charge de la résistance de charge ).

https://en.wikipedia.org/wiki/Current_transformer
https://fr.wikipedia.org/wiki/Transformateur_de_courant

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Note added at 9 days (2023-03-02 16:40:51 GMT)
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@FPC:
"The secondary of a current transformer should not be disconnected from its burden while current is in the primary, as the secondary will attempt to continue driving current into an effective infinite impedance potentially generating high voltages and thus compromising operator safety. For certain current transformers, this voltage may reach several kilovolts and may cause arcing. Exceeding the secondary voltage may also degrade the accuracy of the transformer or destroy it. Output voltage in open operation is limited by core saturation since the primary flux is no longer canceled by secondary flux, smaller current transformers may not actually incur dangerous voltages when operating nominally. Faster current transients from loads being switched on etc. can however still induce dangerous voltage levels due to high current slope."
Quoted from the first web ref above - and confirmed by personal experience in the operation of HV installations many decades ago.