[URGENT] Internship Choice IB-ECM SocGen / Buy-Side Equity Analyst Lazard

Hello Everyone,
I'm just finishing my Master in Finance at ESSEC and I have experience as a Buy-Side Equity Analyst in an L/S Equity Fund pretty prestigious in Paris that got me interviews for the same positions at Rothschild/Lazard (in their equity funds) and in IB in ECM at Credit Suisse (Paris&Zurich)/SocGen.

For now, I got an offer to join the ECM team at SocGen and Lazard as a Buy-Side Equity Analyst. This is my last internship after I would have to apply for full-time (assuming I don't get one in the place I join)

My medium/long term objective is to work in a bigger equity fund in London and I wouldn't mind spending some years in IB/ER if necessary. I have doubts about which one will make my CV more powerful when I will apply for full-time jobs.

From one side, ECM will give me sell-side experience and will help me diversify my CV which means I would have more doors open for full-time. Also, it might be that the IB experience is seen as necessary in London even to join the Buy-side. At the same time, Lazard is a stronger name and would strengthen my experience as a fund analyst which might be beneficial for a fund in London. But I am afraid it will restrict to much my field, given I already have the same experience. Funds in London remain still pretty competitive.

Any thoughts?