It is possible to have a European multiple design application with designs in different Locarno classes. The conditions is that all the designs must relate to ornamentation.
The Community Design Handbook and the OHIM Examination Guidelines refer to a “checkbox on the form” to indicate whether a design is ornamentation. However, this isn’t actually on the form (downloadable or online – D’OH).
However, I have been informed by OHIM that where you the product classes contain the word “ornamentation”, or where this is indicated in an accompanying description, you should not receive a unity of design objection even if you have different Locarno classes for multiple designs in a multiple design application.
1. Several designs may be combined in one multiple application for registered Community designs. Except in cases of ornamentation, this possibility is subject to the condition that the products in which the designs are intended to be incorporated or to which they are intended to be applied all belong to the same class of the International Classification for Industrial Designs.
Guidelines (as above link):
8.2. Unity of Class (Art. 37(1) CDR)
Except in cases of ornamentation (see below) all products indicated for each and every design in a multiple application must fall in the same class of the Locarno Classification.
8.3. Ornamentation (Art. 37(1) CDR)
Ornamentation is an additional and decorative element capable of being applied to the surface of a variety of products without significantly affecting their contours.
In the case of a multiple application in which all designs are for ornamentation, the “unity of class” (see above) does not apply.
Whether an application concerns ornamentation or not is indicated by the applicant either by ticking the corresponding box in the form provided by the Office or by providing an equivalent information where the applicant uses his own form. The decision of the applicant is not subject to in-depth examination. However, an objection will be raised where prima facie the examiner has strong doubts as to whether the design is for ornamentation.