Pros
Work-life balance is good, I had to travel virtually 2 hours to get on the client's site but I was never pressured into doing long working hours, my managers have been very fair with me on that front. Because of the big distance between my home and the client's site, extra benefits were quite good as well. The projects Eurogiciel got are pretty interesting but mostly in aeronautics, military and defense sectors, and it can be nice to show off some of the really complex systems one worked on during a project. The company isn't quoted on the financial markets so the economic turn-down didn't really affect them, which is a positive I guess (but it has its downsides, see below)
Cons
Salary is gross. Salaries are low in France generally speaking but here it's ridiculously low, but this is a by-product of the company having actual money in its lockers, the upper management keeps it for itself and doesn't share with the lowly engineers. There is no growth within the company or visibility of where it wants to go. The motto is just to keep the clients happy, your work doesn't really get recommended if you did good though you can get a right thrashing if you're not up to scratch. Employee morale is low, you can be sent to another site for a client way out of your scope overnight (the ming boggles). Overtime isn't paid (or rather they'll do absolutely anything to not pay you for doing overtime) so no incentive to put any extra effort.