You need to use the CSS property text-align with the value justify to justify in CSS.
Example:
<p style="text-align:justify;">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Cras luctus tincidunt dui, ac rhoncus sem adipiscing eget. Integer gravida ultrices augue id aliquam. In hac habitasse platea dictumst. Curabitur eget tellus odio, id porta nisi. Maecenas aliquet commodo magna ac commodo. Pellentesque sapien massa</p>
So for a table:
<table class="monTableau">...</table>
then you need to add to the CSS file:
.monTableau td{ text-align:justify; }
Thank you :D