Jquery Validation & number field with comma
Browser support may vary, but essentially you want to add an attribute of step="any":

$form['poidsMin'] = array(
    '#type' =&gt; 'number',
    '#title' =&gt; $this-&gt;t('Poids minimum en gramme'),
    '#default_value' =&gt; $frais_port_entity-&gt;get('poidsMin'),
    '#description' =&gt; $this-&gt;t("Poids minimum du produit"),
    '#required' =&gt; TRUE,
    '#attributes' =&gt; ['step' =&gt; 'any'],
);