Don't know whether it's too late or not, but I'll add my thoughts here.
I guess this is a brand new model as it's 2002 and number being GO-. And because of that the mileage has to be in KMs not miles. Peugeot's are very good cars if maintained properly. So go for a trial and feel it. The cars were graded. LX, Rapier, GLX, ST and Executive being the highest grade. Rapier is semi-option while others are full option. Most of the GLX and ST has heat seats, leather seats, electric seats, rear curtain, rain sensors, door lights etc. Executive is all the said options plus headlamp washers and electric sunroof. 406s came with two engine variants 1800cc and 2000cc and a diesel version with 2000cc. Executive's only came with the 2000cc engine. Automatic version is a problematic one because the solenoid valves inside the gearbox fails most of the time and because of that people have converted most auto's into manual. It's a very good car besides that. The normal price of a 406 would be 1.4-1.8 million, Executive's being the highest value. Maintenance is very easy if you find the right guy. Spare parts also can be found easily. A good car for the value having class, comfort and the looks.
So 1.9 million looks quite high. If it's an Executive probably will worth it if it's in mint condition. But it's the buyers opinion that matters. I say if it's good for you go for it. Same theory applies to any other car.