Q:

How to find an internship in OR/Optimization?

I am a master student in operations research with a specialization in operations research. To get my degree, I need to have a 6-month internship (from March to September).
I am preparing my CV and I am browsing some offers in websites like glassdoor or LinkedIn etc. to have an idea about the market. I think that there is not a lot of offers in OR on those websites. I need to start to apply by the end of this month and I don't have an idea where to look. 
So any tips on finding an internship ? 
I am based in France but I am willing to travel.  

A:

On top of the websites you mentioned:

Search on Google! If this is not what you are already doing, this should be on top of your list. Not all ads are on job sites.
Check different companies websites. Some companies ads may not show up in the first pages of your search. So you can focus your search by having some companies in mind. For example, ask your friends or colleagues where they had their internships. That's a good place to start creating a list (on top of having a chance of a referral). If you don't have a list, think of what industry you like to work on and then search for that industry to find companies that are in that industry (e.g. you like to work in retail. Search for companies in retail)
On top of having an up-to-date Linkedin account, upload your resume in all the job websites you know (Indeed, Monster, etc).
If you know of any recruiter on LinkedIn, connect with them. Even if they can't help you now for your internship, that's a good investment for the future.
Don't confine yourself to a keyword. Search for responsibilities or tasks you like to do. You never know how each company brand themselves. You may look for an operations research position and find nothing, while a company can call all of their employees "analyst" or "data scientist" (especially with all the hype around data science!) All that matters is the requirements in the job posting match your interest and expertise. 

A:

From my experience:
1/ Lookup where the students did their internships in the previous years. Contacting those companies might be a good option, as they might be willing to take an intern coming from your program if they were happy with the experience the previous year(s).
2/ Try to find companies working on product linked to Operations Research (companies developing Advanced Planning and Scheduling Software (APS), Transport Management Software (TMS), Workforce Management Software, etc.) and contact them to see if they might be interested to take you as an intern.
3/ As you mentioned that you are based in France, looking at the forum of the ROADEF (http://roadef.org/forum) can also be a good bet.
It is not because a company does not publicly post internship offers that they are not taking interns. Anecdotal evidence: when I was a student the most interesting internship that I got to do was with a company that was not advertising any internship. They were making an interesting product, so I contacted them to know if they would be willing to take me as an intern, and I ended up working on an interesting crew rostering problem with them. Another anecdotal evidence: my company is having some operations research related internships available but they are mainly communicated to university with which we already have an existing link (which does not mean that we would not consider somebody coming from another university for them).

A:

As @Mark L. Stone said your professors, and particularly those you had a course or project could be a good source for the networking. Some websites like this link can be helpful, while I am not sure about those opportunities in Europe. Also, you can find some job (mostly) and internship position posting in the following resources:

IEFac.list
HigherEd Jobs
AcademicJobsOnline.org

