SEO for Multiple Stores in Different Languages

I am in the process of creating a new e-commerce store using the shopping cart Open Cart. OC permits multiple stores from a single database. This functionality combined with subdomains allows stores in different languages to be appear independently of each other. For SEO purposes I acquired a top level domain for each language. So I have xyz.com and xyz.fr for an English language and a French language store. Using subdomains xyz.com in English will appear if the customer types xyz.com in the browser. If someone puts xyz.fr into the browser the shopper will get the same store but in French. The DNS for xyz.fr will be directed to xyz.fr.xyz.com. The English store will be the so-called default store for administration purposes and the French store a secondary store. But the xyz.fr shopper will see only the French language store though he/she can select a different language.

A developer I used to install the stores urged me to create separate stores or else Google would see duplicate content. I followed him and created different totally separate OC stores each with its own database.

Now I have doubts, especially since each foreign language store will also have an English version that the shopper can switch to and so in principle the search engines can see duplicate content across domains. So, before I proceed further with developing the store, I wonder if I should switch back to the subdomain, default store>secondary store model.

Does anyone have any information as to whether from an SEO standpoint I should keep the separate stores or switch back to subdomains?

Your developer wasn't necessarily wrong. It is true that it is better to create separate stores for separate domains. the reason for this is that in the long run you will face issues with customizing something for just one shop.

But in your case you could have one opencart installation with two domains and simply assign the language to each domain. so basically when anyone switches to another language - you have a script that redirects to another domain therefore never showing the second language on the first domain.

It is a relatively simple feature but it needs custom development. ask your developer to do that for you.