#bandeau {
    background-repeat: no-repeat; 
    background-position: center top; 
    width: 900px; 
    height: 350px; 
    margin-top:20px;
}

#divLogoLeft {
    float: left; 
    margin: 20px;
}

#divLogoRight {
    float: right; 
    margin: 20px;
}