Thanks for your answer Steven. I did a quick test but it didn't work. Before to spent hours fighting with the code i'll appreciate if you could have a look to the code I want to use. Or maybe recommend another tested one for me.

The code comes from here: cookieconsent.insites

Something like this:
<link rel="stylesheet" type="text/css" href="//cdnjs.cloudflare.com/ajax/libs/cookieconsent2/3.0.3/cookieconsent.min.css" />
<script src="//cdnjs.cloudflare.com/ajax/libs/cookieconsent2/3.0.3/cookieconsent.min.js"></script>
<script>
window.addEventListener("load", function(){
window.cookieconsent.initialise({
  "palette": {
    "popup": {
      "background": "#000"
    },
    "button": {
      "background": "#f1d600"
    }
  },
  "showLink": false,
  "type": "opt-out"
})});
</script>

But due to the advanced cookie management they say I also have to disable cookies using "callback hook":

The code:
onInitialise: function (status) {
  var type = this.options.type;
  var didConsent = this.hasConsented();
  if (type == 'opt-in' && didConsent) {
    // enable cookies
  }
  if (type == 'opt-out' && !didConsent) {
    // disable cookies
  }
},

onStatusChange: function(status, chosenBefore) {
  var type = this.options.type;
  var didConsent = this.hasConsented();
  if (type == 'opt-in' && didConsent) {
    // enable cookies
  }
  if (type == 'opt-out' && !didConsent) {
    // disable cookies
  }
},

onRevokeChoice: function() {
  var type = this.options.type;
  if (type == 'opt-in') {
    // disable cookies
  }
  if (type == 'opt-out') {
    // enable cookies
  }
},

Could you tell where to put all that code in order to make it work. Or any other solution for these new laws banners that could fit on your site.

Thanks!