You can legally sell 3d printed items in the EU as long as you comply with the following simple rules.
1. Don’t copy
The first and most important rule is to refrain from selling 3D prints of the products created by others.
This includes, for example, 3D printing of the CAD files found on the Internet and, without obtaining the adequate licence, selling the obtained products; creating your own CAD files reflecting others’ CAD files or products or scanning the existing products. The options are many but the result is the same: you’re using the work of others and selling it. It’s never cool.
So, if you’re the manufacturer, don’t copy the products of others. If you’re just the reseller make sure the manufacturer takes responsibility for any possible infringement of third-parties’ IP rights. Specifically, you should be careful not to commit copyright infringement, design infringement or patent infringement.
Interestingly, some trademarks in the EU may be also registered as three-dimensional marks (shape marks), such as this lipstick. Therefore, you should also be careful not to commit a trademark infringement.
Consequently, if you wish to sell 3d printed products that may in any way be protected by intellectual property rights (IPRs), you should consider contacting the author or in any case the owner of the IPRs. When you do that, you could try getting an appropriate licence for manufacturing and selling 3D printed products using their IPRs.
2. Be careful with printing and selling stuff from Thingiverse
Items on Thingiverse and similar websites may be printed out and sold only if there is the author’s specific consent for commercial use of his or her work. However, often the items on these websites will be made available for personal use only. They will grant a Creative Commons licence like the one below (source: https://www.thingiverse.com/thing:4927980 ):
In such cases, by selling these 3D printed items you will violate someone’s IP rights and risk a lawsuit.
3. Be careful with trademarks of others
While selling 3d printed products you must be careful not to use the trademarks of third parties in a way that would violate the EU laws.
First of all, if you sell your own 3D printed products, it’s better that you don’t use others’ trademarks at all. Definitely don’t use them on your products or their packaging. Neither should you use them in the products’ description in a way that could mislead the customers as to the products’ origin or your relationship with the trademark’s holder.
The only legitimate way to use the trademarks of others is when you’re reselling their original products and you must inform the customers about the products’ origin and details. You must not abuse that right by using the trademark that could in any way imply there is a business relationship between you and the trademark’s owner (unless, of course, it exists).
Finally, you may also violate a trademark by printing and selling a three-dimensional trademark of others, as mentioned in the first point of this post.
4. Be careful with the marketing materials
To sell the 3D printed product, you’ll likely use photos of it to attract the attention of potential buyers. Maybe you’ll use also some other pictures and descriptions. When you do that, you must use your own (or licensed to you) marketing materials and write the descriptions of the products by yourself to avoid any copyright infringement.
For example, don’t use the photos made by the CAD files’ creators if they did not authorise you to use them etc. There may be some exceptions but the general rule is you need to get a licence (or acquire rights) to use any copyrighted materials of others.
5. Remember about the manufacturer’s obligations
If you’re printing and selling the 3D printed items in the EU, you need to take care also of all the obligations of manufacturers. While it is not exactly clear who will be liable as a manufacturer in the complex printing process (see my considerations here), it’s highly probable the one commercially printing the products will be considered as one.
The manufacturers are responsible for checking that their products meet EU safety, health, and environmental protection requirements. They need to carry out the conformity assessment, set up the technical file, issue the EU declaration of conformity, and affix the CE marking to a product (see more on CE marking here). Only then can a product be traded on the European Economic Area market. You can start by out checking up on this general information.