I would say if you take it easy it is fine, especially if you are mostly on the flats. Maximum towing weight is really about three things, engine torque/HP, braking ability, and the tongue weight.
Engine Torque and HP is going to dictate your acceleration, the strain on the engine and transmission
as well as your maximum speed for your total weight. Being a little over weight means you will be stressing these components more than intended, however you can probably make up for it by being extra easy on it. Try not to "floor" it to accelerate, be gentle on your accelerator pedal and go nice and easy and the extra strain should be minimal.
MORE important is your braking abilities and I would say that this more often than not dictates what a manufacturer puts down for trailer weights. The manufacturer's are required to meet very specific traffic safety
rules in the US and many other countries and therefore that trailer weight will be published based on what they estimate would meet the maximum "safe" stopping distances for most of those countries. So, if you are over weight leave your self extra stopping distance AND drive slower to compensate as well as minimize strain on your braking system.
Finally, the tounge weight.. This is the maximum weight that your hitch can support as well as your suspension. This is less of a concern as a well balanced trailer should exert nearly no weight on the tounge, but it is something to consider.
AND, one more thing to consider. Read your manual carefully when looking at these weight figures. Often these figures are based on gross vehicle weight + gross trailer weight. Gross vehicle weight (the number on your door tag) is actually a combination of the actual vehicle weight plus a full passenger and cargo load (3 average passengers plus a couple of average suitcases typically). If that is the case what I would recommend is if your trailer is only a 100-200 kilos over the maximum trailer weight then you are probably perfectly fine so long as you are driving the car by yourself and empty.