//add back to store button in empty cart
add_action('woocommerce_cart_is_empty', 'manual_back_to_store_cart_empty');
function manual_back_to_store_cart_empty() { ?>
<a class="button wc-backward" href="/boutique"><?php _e( 'Return to shop', 'woocommerce' ) ?></a>
<?php
}