HTML
<div class="article">
    <div class="article_background"></div>
    <div class="article_content">
        <h1>Abysse Life</h1>
        <br>
        <p>L'île où il faut être !</p>
    </div>

CSS
.article_background {
    width: 100%;
    height: 1000px;
    position: fixed;
    background: url('/abysse/img/bg.jpg') no-repeat;
    background-size: cover;
    background-position: center;
    margin: 0 auto;
    filter: blur(3px);
    z-index: -1;
}

.article_content {
    width: 50%;
    height: 150px;
    position: relative;
    margin: 10% 50%;
    transform: translateX(-50%);
    text-align: center;
    color: #FFF;
    text-transform: uppercase;
    display: flex;
    flex-direction: column;
    justify-content: space-around;
}

.article_content h1 {
    font-size: 60px;
}