Is the Optional Instrument (the Common European Sales Law) consistent with the principle of subsidiarity (Article 5 TEU)? - Journal of European Consumer and Market Law View Is the Optional Instrument (the Common European Sales Law) consistent with the principle of subsidiarity (Article 5 TEU)? by - Journal of European Consumer and Market Law Is the Optional Instrument (the Common European Sales Law) consistent with the principle of subsidiarity (Article 5 TEU)? 2 1 Journal of European Consumer and Market Law