Ok, once someone makes a comprehensive guide for this I'll take this down, but this will be useful for you guys and girls until then. Please keep in mind that there is some mild spoilers ahead.
Bag and Drag
If your really good at this game then you don't need a guide, me, I get tore up a lot so once you get into a firefight at the book store, DON'T GO IN just yet. There is a window to your right that you can use to take out almost anybody on the second floor. Once you can't see anyone step into the door, then go back out to the window. A few enemies have spawned so take them out. Slowing edge the door frame taking out anybody that you can. There should only be one or two at the bottom and your allies can take them.
After you have met up with the French Forces (Sabre) stick to the wooden panel on the left towards the front of the building your in. Be patient, take out anybody you can, After a while I sprinted across the street to the right and cleared the buildings there going up. After a time you will be given a chance to use air support markers. USE THEM! I don't know if they are unlimited but you can use one, inch forward prone and wait for another one, or run and gun, your choice.
Once you get in the tunnels things get a bit easier, you don't have to chase after Volk there isnt a timer or anything, take out each guy as you get to them without exposing yourself. Once you get street level there might be a limit there, just wait until your allies push into the street and charge out to the van.
Edit: Master Fibsey got a 'Volk escaped' message at some point ... but was looking for intel, so might have wasted a lot of time ... (I ran though once more to double check this and yes, Volk can escape, if you are going for intel I would recommend a different difficulty, because it is timed, though you still have a lot of time to work with that you could do both. However, if it gives you this message, I would recommend coming back to that intel later, intel is cumulative across playthroughs.
During the van seen there isn't much you can do. If you are having trouble remember to shoot the gunners then the engine of the vehicles chasing you. I shot a few rounds towards the Hind, but it didn't stick around long enough to hurt me. Once the driver tells you to go back upfront just try to shoot the tires of Volk's vehicle, failing that just lay fire into it until it crashes, slow-mo scene, just kill the guys in the backseat, driver died in the crash for me.
Tips: While your in the air don't shoot yourself (little white boxes) Use 105 for tanks 40 for personnel, and machine gun for helicopters. When your on the ground be slow and safe, Back on the ground Move away from the spawn site, I died 5 times right after spawning. Turn left go up stairs/ When your on the balcony stay prone and deal with the guys in the monument with the sniper rifle that is up there. After a while they will move Volk up the (you'll see a Protect in the monument) so you can start moving up. Be slow edge over the sides, be mindful of windows on the left and balcony s ahead. Let your allies hammer the guys at ground level unless you can get at them. A tank will appear throw smoke. After a time you'll get back in the air again. Use your 40 and machine gun fire at the vehicles chasing the convoy. Take out any and all Hinds, Hinds are Priority, Tanks, then the APC's. the convoy will break down on the bridge. Back on ground get out of the Humvee grab stinger move back and to the right into cover, you can target the tanks without seeing them. Be slow use your sniper and let your allies take all the bullet, you will die here a few times! It's ok, I died more on the bridge than anywhere else on these two levels, make you way up till you hit the blockade, back off here only moving up to throw air support markers, somehow the enemies can get on the rubble to the left and shoot you from cover so be careful of that. There will be lots of talk among your allies, things like "Hit every thing north of us" "Evac in thirty seconds" "last Mag" your close to the end just back up let your allies take the rest of the bullets and watch the rubble to the left.
Oh and a side note, there is a spectacular event that occurs at the end of this mission. Watch it at your own peril, I got ran over (landed on) by the evac chopper watching it.... I felt really dumb. If I forgot a part or you have any questions feel free to leave a comment and I will get back to you. If you leave negative feedback, let me know why, I won't hate you or anything, but I'd like the chance to fix what's wrong so other gamers can profit from this guide until a better one shows up.