title: Bootstrap 4 : '.flex-column' working but not '.justify-content-center'
body: <p>I'm working on some old code and trying to place the content properly on my page but I'm facing a problem : My flex properties are working but not the '.justify-content-...'. </p>
  
  <p>Here's my code : </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous"&gt;
  &lt;script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"&gt;&lt;/script&gt;
  &lt;script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"&gt;&lt;/script&gt;
  &lt;script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"&gt;&lt;/script&gt;
  
  
  &lt;h3 class="titre-jumbotron-video text-center mb-2 mt-3"&gt;Parameters&lt;/h3&gt;
  
  &lt;div class="max-min d-flex flex-column mt-1 mb-4 mx-auto" style="width: 95%"&gt;
  
  &lt;fieldset&gt;
  
    &lt;div class="row"&gt;
      
      &lt;div class="col-4"&gt;
        &lt;div class="d-flex flex-column justify-content-start"&gt;
          &lt;div&gt;
            &lt;p&gt;Some content&lt;/p&gt;
          &lt;/div&gt;
          &lt;div&gt;
            &lt;label&gt;Other type of content : &lt;/label&gt;
            &lt;input type="checkbox"&gt;
          &lt;/div&gt;
        &lt;/div&gt;
      &lt;/div&gt;
  
      &lt;div class="col-4"&gt;
        &lt;div class="d-flex flex-column justify-content-center"&gt;
          &lt;img id="apercuGraphe" src="https://i.kym-cdn.com/photos/images/newsfeed/001/504/739/5c0.jpg" alt="Apercu Graphe" width="200px"&gt;
        &lt;/div&gt;
      &lt;/div&gt;
  
      &lt;div class="col-4"&gt;
        &lt;div class="d-flex flex-column justify-content-end"&gt;
          &lt;div&gt;
            &lt;label&gt;Content 1 : &lt;/label&gt;
            &lt;input type="text"&gt;
          &lt;/div&gt;
          &lt;div&gt;
            &lt;label&gt;Content 2 : &lt;/label&gt;
            &lt;input type="text"&gt;
          &lt;/div&gt;
          &lt;div&gt;
            &lt;label&gt;Content 3 : &lt;/label&gt;
            &lt;select&gt;
              &lt;option value="auto"&gt;Automatic&lt;/option&gt;
            &lt;/select&gt;
          &lt;/div&gt;
        &lt;/div&gt;
      &lt;/div&gt;
  
    &lt;/div&gt;
  &lt;/fieldset&gt;
  
    &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>I think that I'm misunderstanding something but I don't know what.</p>
  
  <p><em>PS: Expand the snippet to see it on a big screen.</em></p>