Then search for contacts (e.g. contacts that have not yet been prospected: http://www.simple-crm-support.com/2015/04/comment-trouver-les-contacts-que-je-nai.html).
Once the results are displayed, click on the button "Assign interests".
A form appears.
In the "Areas of interest to assign to contacts" field, choose the area(s) of interest you want to assign to contacts in the results list.
If you check the "Replace contact interests" box, the interests currently assigned to contacts in the list will be deleted before assigning new interests.
If you uncheck the "Replace contact interests" box, the selected interests in the top field will be added to the existing interests for each contact in the list.
Once the parameters have been set, click on the button "Assign centres of interest".
On the confirmation message, click Ok.
The selected interests are assigned to each contact in the list.