Even if differences in contract law are not a serious obstacle to cross‐border trade in the EU, more common rules would simplify trade. In this respect an optional instrument might have positive results. If these are to be realised, however, the optional instrument must be of very high quality both as to content and presentation. The rules must be, and must by users be seen to be suitable for the contract in question, clear and providing legal certainty. In order to achieve this rules for business‐to‐business contracts should be separated as far as possible from those intended for consumer contracts.
It is also important that the introduction of a European instrument of contract law does not complicate trade with countries outside the EU, a consideration which is largely overlooked in the Green Paper. This means, for example, that sales between businesses should be governed by the UN convention on sales contracts.