<select class="form-control select2" id="sedeID" name="sedeID" style="width: 100%;" required>
    {% for sede in sedes %}
        <option value="{{ sede.sedeID }}">{{ sede.sedeTITULO|striptags }}</option>
    {% endfor%}
</select>

<script type="text/javascript">
    $(document).ready(function() {
        $('.select2').select2();
    });
</script>