It is french. Here's the manufacturer.
fr.wikipedia.org
It has a global presence for the distribution, including in Mexico, but is headquartered from France
To note, Dolethal is non-sterile while Pisabenthal is sterile. I think it has an impact on preservation when in contact, even just a sample, but it's only an assumption from reading the notices, and I'd be glad to be corrected
Combining the french and british notice versions, it says :
- good for 5 years if unopened (FR)
- good for 3 months (UK) after once sampled out (letting the rubber seal on)
- good for 28 days (FR) / 1 month (UK) if opened