Hi Kenty, I have a solution and images to share with you that should not only help you to open your door but also repair the latch itself on each door without it costing you hardly anything at all.
I've posted this elsewhere so apologies for the duplicate post but for ease of finding it here it is again.
I have a Magane Scenic RT Alize T reg, (1999) and the same thing happened to me too. The problem is quite a common one and involves a lever inside the latch mechanism snapping which means that no amount of pulling on the door handles will make them open. You can't see the broken piece as it's inside the latch mechanism itself and everything else will appear to be working just fine.
It's taken me months to work out how to get my door open but as someone said before, once you know how it's easy.
Before you begin, I would like to advise you to do this on a bright sunny day, with plenty of light and I would further advise unless your car is in a lockable garage, start this early in the morning to allow yourself plenty of time to get it done before it gets dark. You won't thank me if you can't lock your car and end up sleeping in it to stop anyone stealing it, lol.
Also consider what you might have to do if you aren't able to follow this repair guide or can't complete the repair for whatever reason. It may be prudent to consider sourcing a replacement latch that you know for certain you can go out and buy if you need to.
Having said that, I didn't and thankfully I was able to repair the latch but I'd have been up the creek if I hadn't been able to.
Ok, now that the cautions are now out the way so let's begin.
I'm assuming at this point that as well as already removing the door card, you've also removed the plasitc anti-interference cover. Mine was white but I can't guarantee that yours will be. If not then it is a git to get out but with brute force and ignorance it should unclip and pull free.
First of all, take a look at the following pic:
This is a close up of the latch mechanism once removed from the door. I have coloured over the levers in question for ease of identification because my camera does not give a particularly clear picture.
You should see an orange lever tip and a grey lever tip, (the actual levers aren't this colour just in case you were wondering, lol).
For the door to open, the orange lever tip has to move to the right. However the grey lever tip is in the way. It is the grey lever tip that gets moved when you pull the handle, (except I'm betting yours isn't doing this as this is what was happening with mine).
Ok, so to open the door, all you have to do is guide a screw driver into the rectangular hole and move the grey lever gently upwards, (here's a zoomed out pic to make it a bit clearer.
You shouldn't need to apply hardly any pressure at all to do this and once you have moved the grey lever tip out of the way, the door will magically pop open. Hey presto!!!
So far so good.
You should now be able to see how to remove the mechanism and I would suggest at this point that you also remove the glass channel which is next to the lock as this will make it much easier to remove the latch. In fact I was unable to get the latch out without doing this.
Once you've got it out, have a look at this last pic.
Now, here comes the tricky part.
You should be looking at a pic with a green arrow and an orange arrow. Also you can see the broken plastic, (YES, PLASTIC!!!) lever in 2 pieces towards the bottom of the pic. This is the little piece that has made your lock useless by so selfish as to break.
The broken plastic lever was taken from where the orange arrow is pointing to and underneath the metal plate that the green arrow is pointing to.
What you're going to need to do is bend the metal plate upwards just enough to allow the broken plastic lever to come out, (green arrow points to the metal plate remember). I used a large screw driver to do this and a bit of brute force. Be careful however not to dame any other components whilst doing this. The lever itself is only held in place by a small round bump on its lower side which acts as a pivot and also keeps it from moving out of position.
I'm hoping at this point that you have found both pieces of the broken plastic lever because if not you're going to find it difficult to do what's required in the next stage.
Thoroughly clean the two parts of the broken lever and carefully work out how they used to join together. Once you've done this superglue the two pieces back together for ease of reference.
I should point out at this time that you're not going to be able to re-use the original lever because unless you know something I don't, no glue is strong enough for this purpose as the first time you tried to open the door it would surely break again leaving you back to square one.
Instead, what you'll need to do is fabricate a new lever, copying the original as precisely as possible.
You can use any number of different materials from aluminium if you happen to have a chunk from another project or a chunk of plastic from that broken item you've got hanging around that you always told the missus would come in handy, lol.
Here what I used though:
It's basically a plastic that softens at a low temp, (around 60 degrees celcius) and generally comes in granular form.
I made a block by melting the beads together and then once cooled I cut and filed it carefully into the right shape.
Remember that it doesn't have to look pretty, just functional.
Once you've crafted your new lever, carefully refit it into the latch making sure that it's located properly, (this really is quite a fiddly process but persevere and you'll get it).
Once you're sure it's in the right place, set the latch down on a firm surface and using a strong tool, (I used the handle of a mallet) Push down hard on the metal plate, (that you previous bent upwards in order to get the lever out) to bend it back into place.
Once you have done this, (assuming that the same part had broken on your latch) you should now have a fully functioning latch mechanism and all it costs you was time and possible a couple of pounds for a suitable piece of material to craft the new lever out of.
Anyway, I hope this helps anyone who may stumble across this post. It took me quite a while to get this sorted but I can assure you my original latch mechanism is now back in the car and is working perfectly. In fact it's far smoother than all the other door latches, lol. I guess the rest may need doing at some point. :-D