hugolaporte on "[Plugin: Polylang] Create posts translations on existing site with large number of records (700)"

Ok I found my solution for custom fields.

$cf = get_post_meta($fr_post_id, 'cf', true);
update_post_meta ($post_id, 'cf', $cf);

Only need a clue to associate the category with the right translation here:

'post_category' => $post_categories