He slit the envelope with a letter opener. He was impressed. The paper was fine quality linen, marbled like the unfranked matching envelope. It was a note from the highest level of the Organization, personally penned by Max.

unnecessary, but just my opinion.

Max’s style, brief to the point of starkness, clear, concise, inviting no explanation, rattled him.

"style.... rattled him." I think you can omit a few of the modifiers in between subject and verb here.

“Humph,” he grunted, “a new broom flexing his muscles.”

I don't know what he means.

The blast of people clamouring to be heard, hit her in the face.

I think this sentence is weaker than the rest of the first few paragraphs. The preceding material is written well, so this sticks out.

a woman dressed in a see-through pink chiffon outfit that did nothing except set her apart from the tastefully dressed crowd

Just a bit too much description that (I suspect) won't contribute to the plot.

wearing a white, starched dickie, deep blue jacket, and trousers that made him look like a penguin,

Again, I know you know precisely what they're wearing, but at this stage of the chapter I just want to get into the story.

her eyes ranged over the crowd searching for a familiar face.

"Range" is not an appropriate verb in this case, I believe.

Centre stage was dominated by the grossly rich: dressed for the occasion, the women dripped with jewels and greeted one another in their tightly knit group with automated cheek-pecks. The men, some oddly boyish—youthful older men, the type able to bed younger women—had their trophies attached to them like limpets. They drank copiously, whispered in their partners’ ears, and laughed discreetly.

This is great writing.

One man in particular caught Renee’s attention

You're demonstrating a good sense of panning (wide) description and redirecting back to the intimacy of Renee's thoughts. Nice work.

“Smooth, huh? He looks like he was born in a tuxedo.”

This needs a dialogue tag- because I initially thought it was Renee's thought. "...said a familiar voice from behind her."

“Byron! I’m so glad to see you,” she said as she turned and looked down on the bearded man who tugged at his collar in an effort to ease his Adam’s apple from its constraints.

I think Renee needs a moment to look at him, so we (reader) can look at him and process the character a little more before Renee begins interacting with him.

she asked playfully as she sedately twirled a full circle.

I'm half hazy on this description. She's twirling, like a pirouette, correct? "sedate" doesn't seem to be an appropriate adjective in that case. It's a neat gesture- don't want you to lose it in the mind of the reader.

champagne ballooned

not sure if "balloon" is the right verb. Balloon, to me, suggests something inflating. I think in the case of champagne, it's either spilling or foaming.

A bitchy remark forming in her mind, she spun to face the clumsy clod, but the cutting words stilled in her throat as her eyes widened at the sight of a pulse-quickening hunk of a man.

This could use a paragraph break.

His scent, a mix of male musk and cologne, triggered steamy thoughts in her mind, and she felt an unaccustomed blush rise on her cheeks.

"steamy thoughts in her mind" seems rather non-descriptive in the context. The words "steamy thoughts" are more romance-novelish.

A current

"What felt like electricity"

This stranger stirred feelings she’d never felt—an instant attraction—electric and breathtaking.

Unnecessary- it's already implied.

And the stranger was no better; he stood in silence shifting his weight from one foot to the other, moving his eyes slowly over her body—his appraisal confident and strong—each inspection longer, heavier; more intimate.

"was no better" implies the narrator knows what the stranger is thinking, which breaks perspective. I think you can simply begin with "He stood in silence..."

As her pulse settled to a more normal rhythm, she turned and started to walk away.

"pulse" in this case should probably be "heart beat" because it's 3PL, so unless she specifically holds her hand to an artery she can't really feel her pulse. But she can feel her heart rate.

A hand resting lightly on her shoulder spun her around. Her stomach somersaulted, her body felt odd: sensitive, aware. She felt the man’s breath against her cheek; saw the five-o’clock shadow that shaded his jaw, and best of all, the mouth: a mouth seasoned with experience that smiled easily and grinned wickedly. Lust threatened to sideline her effrontery.

This is a tad overwritten for me.

Also, you're introducing new actions, and each time you do, I think there should be a paragraph break.

Renee’s throat burned and sealed closed.

I think this is overdramatic.

“Now that we’ve met, my life will never be the same.” The compliment was accompanied with a raising and lowering of the eyebrows.

He's beginning to come off like a villain, now. At this point, I'm not sure what your intentions are, but the line of dialogue seems unrealistic if he were trying to be sincere. It sound campy, and for villains that works.

Liam’s face twisted in surprise and Renee saw something in his eyes, something intense, hot, and dangerous. He flung his head back and laughed—an infectious laugh that set heads turning. Everyone in the room stopped and stared before resuming their chatter.

Again, a little overwritten. Your characterization of Renee is excellent in her actions and dialogue. But when we get into her inner monologue I start to skim.

cocking his head to one side and cupping his hand behind his left ear.

A little too choreographed for fiction, in my opinion.

Silently she regarded him with his long legs braced and hands resting lightly on his hips; she felt the flush on her face deepen—it felt good to be tempted.

This line felt out-of-place to me. For pacing's sake, it just broke the flow of their exchange.

Renee’s heart skipped a beat at the seductive promise in Liam’s voice. She could feel the blood pulse in her veins, and a strange heaviness in the pit of her stomach. She felt emotionally charged, all dressed up and ready—gloriously ready. From under her mascara-highlighted eye lashes she looked up into his face and hesitated.

It's doing some of the same stuff I mentioned already. But another thing-- the line "From under her mascara highlighted eyelashes" is a break in perspective, because she can't see her own eyelashes unless she's looking in a mirror.

“You’re teasing aren’t you?” Liam asked.

What is this in response to?

He said nothing more, just looked at her, his chest rising and falling with quickened breaths; his eyes were focussed: alert, alive, studying her with curiosity. His silence conveyed strength and power.

A bit much.

struggling with the power he seemed to have over her. She looked away and stared across the room as she felt a sudden stab of panic. She wasn’t used to male domination; she always picked her own marks. A warm hand on her bare arm drew her eyes back to Liam’s face. His scent went straight to her brain. She felt his hot breath, only inches from her face, warm her lips; she imagined kissing the seasoned-with-experience mouth, tasting it, sharing its secrets—and giving up some of her own. Are you crazy? Renee’s brain screamed. With supreme effort she pulled back, shocked by her lascivious thoughts.

You can probably guess what my comment is.

Liam’s eyes sparkled and, as if he had read her mind, his lips curled in a cheeky smile. “Your phone number!” he said, as he slid a neatly folded handkerchief from his pocket, Renee pulled a lipstick from her evening bag, and with hands shaking scrawled the numerals on the linen—big and bold. She wanted to be found.

This is all well written, although at times I felt it overwritten to the point of wavering off topic. But I've isolated this part here because it's your last two paragraphs-- where I want to know the point of this chapter.

Your teaser prologue is interesting, but I've forgotten what happens in it- except for the fact that Renee is to be contacted in relation to a hit.

The opening of the chapter, with Renee contemplating having to give a speech, begins well and moves well into the party scene. But then the plot seems to come to a complete stop when she encounters the mysterious stranger. To me, the plot is lost and we move into a lot of (forgive me for saying so) Romance novel -esque writing. I get the feeling this is going to be a spy thriller- it's got a Bond type of thing going for it. Much of it is written well. Your ability with words, the sound of your sentences, and eloquent vocabulary are all bonuses. Never did I feel a word was too intellectual for the context. But the end of the chapter left me feeling it needed more. I think Renee should give her speech by the end of the chapter, giving something for us to be interested enough to read Chapter 2-- beyond her lustful thoughts and prospect for a date (unless this is, in fact, a romance novel).

Hope this feedback helps you out. Good luck.