I tried a lot of things but even if I do this;

<div t-attf-class="form-group #{error and 'categ_ids' in error and 'has-error' or ''}">

     <label class="col-md-3 col-sm-4 control-label" for="name">You are an : </label>

    <div class="col-md-7 col-sm-8"> <input type="text" name="categ_ids" t-att-name="categ_ids" t-attf-value="#{categ_ids or ''}">    </input> </div>

</div>

where the value of the field is "investor,entrepreneur", knowing that the tags "investor" and "entrepreneur" already exist in db, it doesn't create the tags.

This works in a csv upload however.

Of course, the best solution would be to have checkboxes for the user to click but if I could already upload my text field with comma separated tags, it would be great.