div#colonne1 {

	float: left;
	width: 20%;
	background: lightblue;
}

div#colonne2 {
	background-color: red;

	float: right;
	width: 30%;
	background: burlywood;
}

div#centre {
	margin-left: 170px;
	margin-right: 310px;
	overflow: hidden;
}

.fixelemnt{

}