How to clear Prestashop classes cache?

Modules may add an override to a default behavior, and PrestaShop takes care of resetting the «/cache/class_index.php» file. But sometimes you need to add that overriding code yourself, manually uploading the file to your server. In that case, you need to trigger the regeneration of the «/cache/class_index.php» file yourself. This is done simply by deleting the file: if PrestaShop cannot find the file, it will regenerate it, taking all the overrides into account. It is the same when manually removing an override: in order to reinstate the default behavior, you must delete the «/cache/class_index.php» file.