JSFiddle - React, Tailwind, and code Playground

HTML

<form>
  <label>Test PHPfrance :</label>
  <input name="T2_PRE" type="text"  class="Maj" pattern="^[A-ZÁÀÂÄÃÅÇÉÈÊËÍÌÎÏÑÓÒÔÖÕÚÙÛÜÝŸÆŒa-záàâäãåçéèêëíìîïñóòôöõúùûüýÿæœ '-]+$"/>
</form>

CSS

input:invalid {
    outline: 2px solid red;
}