thanks for your questions and suggestion. It is long list, let me asnwer them one by one
1. Is there some function on front-end to show all products of one seller? Would be really useful and necessary! OK, i found the plugin you have!
Yes, you are right.
2. How is the payment of commission fees for seller to shop owner handled when order payment is set as directly from buyer to seller? is this the paypal module you offer or can there be used any other payment modules? Or are the payment modules only valid for transactions/orders of products from customer to seller or shop owner?
The payment function is included in Seller Commission module.
It uses Paypal to perform payment. Both seller and store needs a Paypal account.
3. The seller rating module is not installed on this demo, right? Is there a possibility to see it live?
I have just installed to the same demo site. You can have a look now.
4. Is there the possibility for a seller to add his own terms and conditions or is there only one terms and conditions from shop owner valid for all sales and sellers?
There is only one terms & conditions from store owner at this moment.
5. is there a possibility to search for sellers through search function? Can this be added easily!?
This products list page (above 1), there is a full list of sellers page, we can add search seller function on that page, but need some customization.
6. Is there a german translation for your modules front-end, back-end?
You have to use PrestaShop translation function to translate related text into Germany.
PrestaShop has integrated Google translation function so it is very easy to do that.
7. Is there an automated invoice tool (like in prestashop for client orders, but for commission transactions between shop owner and seller? Or do invoices have to be created manually!?
No, currently there is no invoice function between seller and store owner.
8. The Coupon function does not work for sellers individually only for show owner globally on all products of sellers?
yes, you are right. The coupon applies to all sellers.
Sorry, I don't know this module, I can not give any comment on this.
10. After deinstalling your addons, can I return the shop into a standard prestashop, but still with all products, also the ones for sellers before! Meaning, can I export a sellers products and import them into a standard prestashop?
Yes, you can do that.
I didn't add new field or modify any fields in existing PrestaShop tables. so there is no problem.
11. Do other modules installed work as planed or are there any restrictions you can define after i installed your multiseller module?
It is difficult to say, in most cases it should works. My modules are developped based on PrestaShop architeture, it should not affect other modules, as long other module are using prestashop standard.
12. If set to "Store collects all payments" how are the shipping costs handled and how if set to "Seller collects payments"?
The module dose not have any control on handle shipping, it is the same.
each seller now can set their own private shipping fee/carriers. But handling fee is the same.
I suggest you set handling fee to 0, let each seller to manage it in shipping fees.
13. if set to "Store collects all payments" then there is an order displayed in the owner account and aswell in the different sellers account! it would make sense, that only shop owner can set payment status "eg. payment accepted" BUT as I figured out, also the different sellers can change the payment status. Even after the shop owner changed status to paid, if only one seller changes the payment status of this order to "unpaid", this order is shown as unpaid again in the admin account! This seems to be a problem, no?
You can change permission settings at "Permission" tab to disallow seller to change the order status. Make it read only for sellers.
Hope I have clarified all your questions.