Welcome from another French member! 😀
A useful tool is the search here - putting the reference in the advanced search function and returning results only from the private sale section. See example at the bottom.
This gives you an overview of previous sales and a realised price point. Of course, bear in mind that watches are all different (condition, exact dial layout, case material etc., date or not etc, and location)… all of this will impact price. You can also search eBay sold listings. Only use sold items for reference price point, current listings can sometimes sit for months without being sold.
You can set up alerts for specific references in eBay for instance. Shipping is very usual these days, locating the example you’re after locally is harder and harder, especially if you’re not in a big city. That said it’s worth keeping an eye on local platforms. But be aware of scams and if unsure, ask for advice like you did here… with the best pictures possible. Sales on OF are generally much more scrutinised… and there is track record usually for most sellers. It’s works pretty well. I would narrow down the search within the EU only if you’re not familiar with shipping, to avoid nasty custom surprises.
People generally like no date - because it doesn’t break the symmetry of the dial. With a date, you might have to set it up each time you wear the watch (if not a daily). I personally prefer no date too for aesthetic reasons, but that’s personal. I don’t set the date on the watches I wear anyway, only the time. This reference without date is 14381.
To make the search easier, you can also possibly extend to references that have a similar style - for instance 2852, 2782 etc.
Box and papers is nice and definitely a small plus, but wouldn’t worry too much about these. You don’t wear them. You can always buy a box separately if you feel the urge.
The thing that is important though, is to anticipate a servicing cost (300-500€ these days at an Omega certified watchmaker). If people claim the watch has been serviced, there should normally be some paper to explain the extend of the service. If there isn’t, best to assume it hasn’t been.
Bonne chance avec la recherche!
Example of search on the forum.
https://omegaforums.net/search/3511...[nodes][0]=40&c[title_only]=1&o=relevance&g=1